X chromosome variants are associated with male fertility traits in two bovine populations

BACKGROUND

Twenty-five phenotypes were measured as indicators of bull fertility (1099 Brahman and 1719 Tropical Composite bulls). Measurements included sperm morphology, scrotal circumference, and sperm chromatin phenotypes such as DNA fragmentation and protamine deficiency. We estimated the heritability of these phenotypes and carried out genome-wide association studies (GWAS) within breed, using the bovine high-density chip, to detect quantitative trait loci (QTL).

RESULTS

Our analyses suggested that both sperm DNA fragmentation and sperm protamine deficiency are heritable (h2 from 0.10 to 0.22). To confirm these first estimates of heritability, further studies on sperm chromatin traits, with larger datasets are necessary. Our GWAS identified 12 QTL for bull fertility traits, based on at least five polymorphisms (P < 10-8) for each QTL. Five QTL were identified in Brahman and another seven in Tropical Composite bulls. Most of the significant polymorphisms detected in both breeds and nine of the 12 QTL were on chromosome X. The QTL were breed-specific, but for some traits, a closer inspection of the GWAS results revealed suggestive single nucleotide polymorphism (SNP) associations (P < 10-7) in both breeds. For example, the QTL for inhibin level in Braham could be relevant to Tropical Composites too (many polymorphisms reached P < 10-7 in the same region). The QTL for sperm midpiece morphological abnormalities on chromosome X (QTL peak at 4.92 Mb, P < 10-17) is an example of a breed-specific QTL, supported by 143 significant SNPs (P < 10-8) in Brahman, but absent in Tropical Composites. Our GWAS results add evidence to the mammalian specialization of the X chromosome, which during evolution has accumulated genes linked to spermatogenesis. Some of the polymorphisms on chromosome X were associated to more than one genetically correlated trait (correlations ranged from 0.33 to 0.51). Correlations and shared polymorphism associations support the hypothesis that these phenotypes share the same underlying cause, i.e. defective spermatogenesis.

CONCLUSIONS

Genetic improvement for bull fertility is possible through genomic selection, which is likely more accurate if the QTL on chromosome X are considered in the predictions. Polymorphisms associated with male fertility accumulate on this chromosome in cattle, as in humans and mice, suggesting its specialization.

RAPID COMMUNICATION: Multi-breed validation study unraveled genomic regions associated with puberty traits segregating across tropically adapted breeds1

An efficient strategy to improve QTL detection power is performing across-breed validation studies. Variants segregating across breeds are expected to be in high linkage disequilibrium (LD) with causal mutations affecting economically important traits. The aim of this study was to validate, in a Tropical Composite cattle (TC) population, QTL associations identified for sexual precocity traits in a Nellore and Brahman meta-analysis genome-wide association study. In total, 2,816 TC, 8,001 Nellore, and 2,210 Brahman animals were available for the analysis. For that, genomic regions significantly associated with puberty traits in the meta-analysis study were validated for the following sexual precocity traits in TC: age at first corpus luteum (AGECL), first postpartum anestrus interval (PPAI), and scrotal circumference at 18 months of age (SC). We considered validated QTL those underpinned by significant markers from the Nellore and Brahman meta-analysis (P ≤ 10-4) that were also significant for a TC trait, i.e., presenting a P-value of ≤10-3 for AGECL, PPAI, or SC. We also considered as validated QTL those regions where significant markers in the reference population were at ±250 kb from significant markers in the validation population. Using this criteria, 49 SNP were validated for AGECL, 4 for PPAI, and 14 for SC, from which 5 were in common with AGECL, totaling 62 validated SNP for these traits and 30 candidate genes surrounding them. Considering just candidate genes closest to the top SNP of each chromosome, for AGECL 8 candidate genes were identified: COL8A1, PENK, ENSBTAG00000047425, BPNT1, ADAMTS17, CCHCR1, SUFU, and ENSBTAG00000046374. For PPAI, 3 genes emerged as candidates (PCBP3, KCNK10, and MRPS5), and for SC 8 candidate genes were identified (SNORA70, TRAC, ASS1, BPNT1, LRRK1, PKHD1, PTPRM, and ENSBTAG00000045690). Several candidate regions presented here were previously associated with puberty traits in cattle. The majority of emerging candidate genes are related to biological processes involved in reproductive events, such as maintenance of gestation, and some are known to be expressed in reproductive tissues. Our results suggested that some QTL controlling early puberty seem to be segregating across cattle breeds adapted to tropical conditions.

Multitrait meta-analysis identified genomic regions associated with sexual precocity in tropical beef cattle

Multitrait meta-analyses are a strategy to produce more accurate genome-wide association studies, especially for complex phenotypes. We carried out a meta-analysis study for traits related to sexual precocity in tropical beef cattle (Nellore and Brahman) aiming to identify important genomic regions affecting these traits. The traits included in the analyses were age at first calving (AFC), early pregnancy (EP), age at first corpus luteum (AGECL), first postpartum anoestrus interval (PPAI), and scrotal circumference (SC). The traits AFC, EP, and SCN were measured in Nellore cattle, while AGECL, PPAI, and SCB were measured in Brahman cattle. Meta-analysis resulted in 108 significant single-nucleotide polymorphisms (SNPs), at an empirical threshold P-value of 1.39 × 10-5 (false discovery rate [FDR] < 0.05). Within 0.5 Mb of the significant SNP, candidate genes were annotated and analyzed for functional enrichment. Most of the closest genes to the SNP with higher significance in each chromosome have been associated with important roles in reproductive function. They are TSC22D2, KLF7, ARHGAP29, 7SK, MAP3K5, TLE3, WDR5, TAF3, TMEM68, PPP1R15B, NR2F2, GALR1, SUFU, and KCNU1. We did not observe any significant SNP in BTA5, BTA12, BTA17, BTA18, BTA19, BTA20, BTA22, BTA23, BTA25, and BTA28. Although the majority of significant SNPs are in BTA14, it was identified significant associations in multiple chromosomes (19 out of 29 autosomes), which is consistent with the postulation that reproductive traits are complex polygenic phenotypes. Five proposed association regions harbor the majority of the significant SNP (76%) and were distributed over four chromosomes (P < 1.39 × 10-5, FDR < 0.05): BTA2 (5.55%) from 95 to 96 Mb, BTA4 (5.55%) from 94.1 to 94.8 Mb, BTA14 (59.26%) from 24 to 25 Mb and 29 to 30 Mb, and BTA21 (5.55%) from 6.7 Mb to 11.4 Mb. These regions harbored key genes related to reproductive function. Moreover, these genes were enriched for functional groups associated with immune response, maternal-fetal tolerance, pregnancy maintenance, embryo development, fertility, and response to stress. Further studies including other breeds and precocity traits could confirm the importance of these regions and identify new candidate regions for sexual precocity in beef cattle.

Genomic association for sexual precocity in beef heifers using pre-selection of genes and haplotype reconstruction

Reproductive traits are of the utmost importance for any livestock farming, but are difficult to measure and to interpret since they are influenced by various factors. The objective of this study was to detect associations between known polymorphisms in candidate genes related to sexual precocity in Nellore heifers, which could be used in breeding programs. Records of 1,689 precocious and non-precocious heifers from farms participating in the Conexão Delta G breeding program were analyzed. A subset of single nucleotide polymorphisms (SNP) located in the region of the candidate genes at a distance of up to 5 kb from the boundaries of each gene, were selected from the panel of 777,000 SNPs of the High-Density Bovine SNP BeadChip. Linear mixed models were used for statistical analysis of early heifer pregnancy, relating the trait with isolated SNPs or with haplotype groups. The model included the contemporary group (year and month of birth) as fixed effect and parent of the animal (sire effect) as random effect. The fastPHASE® and GenomeStudio® were used for reconstruction of the haplotypes and for analysis of linkage disequilibrium based on r² statistics. A total of 125 candidate genes and 2,024 SNPs forming haplotypes were analyzed. Statistical analysis after Bonferroni correction showed that nine haplotypes exerted a significant effect (p<0.05) on sexual precocity. Four of these haplotypes were located in the Pregnancy-associated plasma protein-A2 gene (PAPP-A2), two in the Estrogen-related receptor gamma gene (ESRRG), and one each in the Pregnancy-associated plasma protein-A gene (PAPP-A), Kell blood group complex subunit-related family (XKR4) and mannose-binding lectin genes (MBL-1) genes. Although the present results indicate that the PAPP-A2, PAPP-A, XKR4, MBL-1 and ESRRG genes influence sexual precocity in Nellore heifers, further studies are needed to evaluate their possible use in breeding programs.

Assessing the value of phenotypic information from non-genotyped animals for QTL mapping of complex traits in real and simulated populations

Background

QTL mapping through genome-wide association studies (GWAS) is challenging, especially in the case of low heritability complex traits and when few animals possess genotypic and phenotypic information. When most of the phenotypic information is from non-genotyped animals, GWAS can be performed using the weighted single-step GBLUP (WssGBLUP) method, which permits to combine all available information, even that of non-genotyped animals. However, it is not clear to what extent phenotypic information from non-genotyped animals increases the power of QTL detection, and whether factors such as the extent of linkage disequilibrium (LD) in the population and weighting SNPs in WssGBLUP affect the importance of using information from non-genotyped animals in GWAS. These questions were investigated in this study using real and simulated data.

Results

Analysis of real data showed that the use of phenotypes of non-genotyped animals affected SNP effect estimates and, consequently, QTL mapping. Despite some coincidence, the most important genomic regions identified by the analyses, either using or ignoring phenotypes of non-genotyped animals, were not the same. The simulation results indicated that the inclusion of all available phenotypic information, even that of non-genotyped animals, tends to improve QTL detection for low heritability complex traits. For populations with low levels of LD, this trend of improvement was less pronounced. Stronger shrinkage on SNPs explaining lower variance was not necessarily associated with better QTL mapping.

Conclusions

The use of phenotypic information from non-genotyped animals in GWAS may improve the ability to detect QTL for low heritability complex traits, especially in populations in which the level of LD is high.

Central nervous system vasculitis associated with hepatitis C virus infection: a brain MRI-supported diagnosis

BACKGROUND

The Hepatitis C virus (HCV) infection is associated with various extrahepatic manifestations, being the Central Nervous System (CNS) rarely involved.

CASE REPORT

We report a case of a 54 year-old black man with arterial hypertension who presented with progressively worsening headaches, apathy, somnolence and left hemiparesis. Brain MRI showed an acute ischemic lesion in the left anterior cerebral artery (ACA) and an old ischemic infarct in the right ACA territory. Brain MRI with gadolinium revealed mural thickening and contrast enhancement of the A1 and A2 segments of the ACAs, of the middle and distal basilar artery and of the P1 segment of the left posterior cerebral artery, suggesting active vasculitis. Digital angiography confirmed those irregularities and stenosis. Laboratory evaluation revealed ESR (73 mm/h), transaminase elevation, elevated HCV viral load genotype 2, positive IGRA, negative cryoglobulins, CSF protein elevation with oligoclonal bands (mirror pattern) and no pleocytosis; investigation excluded other infectious causes. Pegylated interferon alpha-2a and ribavirin, corticotherapy and tuberculosis prophylaxis were started with clinical and imagiological improvement.

CONCLUSION

The typical inflammation signs of the vascular wall demonstrated by the gadolinium-enhanced MRI strengthened the hypothesis of CNS vasculitis. The association with HCV infection is rare but should be investigated once specific therapeutic is required.

Can a clinical classification of stroke predict complications and treatments during hospitalization?

The predictive value of the Oxfordshire Community Stroke Project ischemic stroke classification for acute stroke complications, therapeutic interventions and disability at discharge was investigated in 297 consecutive first-ever acute stroke patients. More than one medical complication (odds ratio, OR = 2.2), fever (OR = 2.5) and dependency (Rankin grade > 2) at discharge (OR = 2.3) were more frequent in intracerebral hemorrhage patients. Fever and urinary tract infections were the most common complications among ischemic stroke patients. Both were more frequent in total anterior circulation infarct (TACI) patients (OR = 11.5 and OR = 3.7). Neurological deterioration was observed in about 10% of TACI and posterior circulation infarct (POCI) patients. Dependency at discharge was more frequent in TACI patients (OR = 10.3). Logistic regression analysis identified ischemic stroke subgroups (OR = 8.4) and medical complications (OR = 3.8) as predictors of poor outcome (Rankin score > or = 4). A clinical classification is useful to predict possible medical and neurological complications in the acute phase, death and dependency at discharge.

Diagnosis of stroke by the nonneurologist. A validation study

BACKGROUND AND PURPOSE

The first medical contact of an acute stroke victim is often a nonneurologist. Validation of stroke diagnosis made by these medical doctors is poorly known. The present study seeks to validate the stroke diagnoses made by general practitioners (GPs) and hospital emergency service physicians (ESPs).

METHODS

Validation through direct interview and examination by a neurologist was performed for diagnoses of stroke made by GPs in patients under their care and doctors working at the emergency departments of 3 hospitals.

RESULTS

Validation of the GP diagnosis was confirmed in 44 cases (85%); 3 patients (6%) had transient ischemic attacks and 5 (9%) suffered from noncerebrovascular disorders. Validation of the ESP diagnosis was confirmed in 169 patients (91%); 16 (9%) had a noncerebrovascular diagnosis. Overall, the most frequent conditions misdiagnosed as stroke were neurological in nature (cerebral tumor, 3; subdural hematoma, 1; seizure, 1; benign paroxysmal postural vertigo, 1; peripheral facial palsy, 2; psychiatric condition, 6; and other medical disorders, 7).

CONCLUSIONS

In the majority of cases, nonneurologists (either GPs or ESPs) can make a correct diagnosis of acute stroke. Treatment of acute stroke with drugs that do not cause serious side effects can be started before evaluation by a neurologist and CT scan.

Headaches in intracerebral hemorrhage survivors

Few data exist on headache in survivors of acute cerebrovascular disease. During the second year of follow-up of a cohort of intracerebral hemorrhages (ICH), the lifetime history of headache before stroke and 2 years after stroke was characterized through a neurologic interview and a headache questionnaire. Headaches were classified following the International Headache Society classification categories. Disability (Rankin scale) and depression (CERAD depression scale) were also evaluated. Ninety survivors were interviewed. Comparing the distribution of pre- and post-ICH headaches, 24 subjects (27%) never had headaches, 39 subjects (43%) had ongoing headaches, 10 subjects (11%) complained of headaches only after ICH, and 17 subjects' (19%) headaches remitted after ICH. There was usually a delay of weeks or months between ICH and the first headache episode. Poststroke headaches were in general less severe and frequent than prestroke headaches. New-onset headaches after ICH were mainly of the tension type and were significantly associated with depression but not with new intracranial lesions. Headaches in remission after ICH were related to acute alcohol consumption and migraines. Chronic post-ICH headaches are usually tension type and occur in association with depression. Remission of headaches after ICH is related to removal of headache precipitants (alcohol) and possibly to structural or functional changes of the trigeminovascular system secondary to intracranial bleeding.

Diagnosis of transient ischemic attack by the nonneurologist. A validation study

BACKGROUND AND PURPOSE

Interobserver reliability of the diagnosis of transient ischemic attack (TIA) is low, and diagnosis of TIA made by nonneurologists is often erroneous. We sought to validate the diagnosis of TIA made by general practitioners (GPs) and by hospital emergency service physicians (emergency MDs).

METHODS

A list of 20 neurological symptoms was distributed to 20 GPs and 22 neurologists who graded the compatibility of each symptom with the TIA diagnosis. At least two neurologists validated TIA diagnoses made by GPs for patients under their care or by emergency MDs.

RESULTS

Compared with neurologists, GPs considered "confusion" and "unexplained fall" more often compatible with TIA and "lower facial palsy" and "monocular blindness" less often compatible with TIA. Validation of diagnosis by GP was confirmed in 10 patients (19%); 26 patients had strokes, and 16 (31%) had a noncerebrovascular disorder. Validation of diagnosis by emergency MD was confirmed in 4 patients (13%); 10 patients had strokes, and 17 (55%) had noncerebrovascular disorders. The most frequent conditions misdiagnosed as TIAs were transient disturbances of consciousness, mental status, and balance.

CONCLUSIONS

The TIA concept is understood differently by neurologists and nonneurologists. GPs and emergency MDs often label minor strokes and several nonvascular transient neurological disturbances as TIAs. Until this misconception of TIA is changed, the term TIA should probably be avoided in the communication between referring physicians and neurologists. If not referred to a neurologist, one third to one half of patients labeled with a diagnosis of TIA will be inappropriately managed.

Headache in intracerebral hematomas

OBJECTIVES

We sought to describe the frequency and location of headache in intracerebral hematoma (ICH) and to analyze its clinical and CT predictors by means of multivariate analysis.

BACKGROUND

Headache is more common in intracerebral hemorrhage than in ischemic stroke, and its frequency varies with hematoma location, but the pathophysiologic mechanisms of headache associated with ICH are not fully known.

METHODS

We examined a cohort of 289 patients with ICH during a 14-month period in a university hospital. Clinical, including the presence and location of headache, and CT features were collected by two neurologists.

RESULTS

One hundred and sixty-five (57%) patients with ICH had a headache at the onset of their stroke. Headache was more common in cerebellar and lobar hemorrhages than in deep ones (thalamic, caudate, capsuloputaminal, brainstem). Headache was also more common in women, patients younger than 70 years, those who vomited, and those with meningeal signs, a Glasgow Coma Scale score < 10, a hematoma volume > 10 ml or CT evidence of intraventricular or subarachnoid bleeding, moderate to severe hydrocephalus, or transtentorial herniation or midline shift. In multiple logistic regression analysis, only meningeal signs (odds ratio [OR] = 2.3), cerebellar or lobar location (OR = 2.1), transtentorial herniation (OR = 1.8), and female gender (OR = 1.6) were significant predictors of headache at the onset of ICH.

CONCLUSIONS

Hematoma location, meningeal signs, and gender are more predictive of headache than hematoma volume, suggesting that headache is more often related to the activation of an anatomically distributed system in susceptible individuals and to subarachnoid bleeding than to intracranial hypertension.

Carotid stenosis associated with atrial fibrillation

PURPOSE AND SETTING

To describe the prevalence and risk factors for carotid stenosis in TIA/stroke patients with non valvular atrial fibrillation (AF) and to compare clinical and CT characteristics of TIA/stroke in AF patients with and without carotid stenosis.

SUBJECTS

50 TIA/stroke patients with AF who had ultrasound investigation of the extracranial vessels, included in a prospective hospitalar registry.

RESULTS

Twenty-two patients had some degree of carotid stenosis, but only 5 had more than 50% stenosis, including one with occlusion. Stenosis was neither more frequent nor more severe on the symptomatic side. Smokers were significantly more frequent in AF patients with > 50% stenosis. Clinical and CT features were quite similar in patients with and without carotid stenosis.

CONCLUSION

The association in a TIA/Stroke patient of AF and severe carotid stenosis on the symptomatic side is exceptional. TIA/strokes related to carotid stenosis cannot be identified by their clinical/CT characteristics. Management of these patients must be decided by stratification of risk of recurrence for AF and from carotid stenosis and balance of these risks with that of endarterectomy.

Headache associated with transient ischemic attacks

Sixty (29%) of 205 consecutive patients with transient ischemic attacks registered in a hospital stroke data base had headache within 72 hours of onset. Headache was significantly more common in nonsmokers (odds ratio = 2.8; 95% confidence interval = 6.7 to 1.2). Headache was infrequent in patients with amaurosis fugax, and was not significantly associated with any other particular clinical presentation of transient ischemic attack. Headache was more common in vertebrobasilar (33%) than in carotid distribution (24%) episodes, and was not rare in transient ischemic attacks presenting as lacunar syndromes (29%). Headache was less frequent in patients whose computerized tomograms showed an infarct appropriate to the symptoms (odds ratio = 0.2; 95% confidence interval = 0.02 to 1.4). A diffuse headache was more common in patients with lacunar events than in patients with cortical attacks (odds ratio = 3.0; 95% confidence interval = 13 to 0.07). No other association was found between headache location and the presumed involved vascular territory. Headache in patients with transient ischemic attacks is poorly related/explained by the clinical characteristics of the ischemic event.

A multivariate study of headache associated with ischemic stroke

Thirty-four percent of 182 ischemic stroke patients registered during 1 year in a prospective hospital stroke data base complained of headache within a 72-hour interval of stroke onset. Headache was more common in patients under 70 years of age, in nonsmokers, in those with a past history of migraine, and in subjects presenting transient loss of consciousness, nausea/vomiting, or visual field defects. Headache was more frequent in vertebrobasilar (57%) than in carotid (20%) territory strokes, more so in posterior cerebral artery (90%) and cerebellar infarcts (80%), and was infrequent in subcortical infarcts (7%) and lacunes due to single perforator disease (9%). In multiple regression analysis, vertebrobasilar stroke (odds ratio 6.9), lacuanr stroke (odds ratio 0.06), and past history of migraine (odds ratio 6.7) were significant independent predictors of headache, suggesting that ischemic stroke location is the major determinant of stroke-associated headache, most probably related to activation of the trigeminovascular system, whose threshold may be modified by individual susceptibility.

Perimesencephalic and nonperimesencephalic subarachnoid haemorrhages with negative angiograms

BACKGROUND

van Gijn and co-workers identified "Perimesencephalic haemorrhage" (PM) as distinct, benign, non-aneurysmal subarachnoid haemorrhage. However, there is only one retrospective series of this entity outside the Netherlands.

PURPOSE

to confirm (or not) the benign nature of perimesencephalic subarachnoid haemorrhage by evaluating its clinical course and long-term follow-up in a consecutive series of patients admitted to a University Hospital.

METHODS

Patients with subarachnoid haemorrhage and negative cerebral angiography admitted between January 1985 and April 1992 were classified according to the distribution of blood on a CT scan performed within 72 hours after onset, in perimesencephalic and non-perimesencephalic haemorrhages. Demographic and clinical data (collected consecutively), complications and long-term follow-up (obtained by chart review and follow-up by mail) were compared in the two groups.

RESULTS

Seventy one cases, 36 perimesencephalic and 35 nonperimesencephalic were included. Sex and age distribution were similar in the two groups. A normal examination on admission was the rule in the perimesencephalic group. Only one patient with perimesencephalic haemorrhage had a complication--transient neurological signs during angiography--and there were no deaths or morbidity during follow-up. In the non-perimesencephalic group three patients rebleed, four developed hydrocephalus and two had delayed cerebral ischaemia. Mean duration of follow-up was 27.6 months for the perimesencephalic and 30.8 months for the non-perimesencephalic group. After discharge there was a fatal rebleed in the latter group. Fifteen percent of the subjects (11% of the perimesencephalic group and 20% of the non-perimesencephalic group) retired from work during the follow-up period. Headaches and depression were found in similar percentages (22-25%) in both groups.

CONCLUSIONS

This study confirms that perimesencephalic haemorrhage is a distinct entity within the larger group of subarachnoid haemorrhage with negative angiograms, with a good short term and long-term prognosis, and no need for repeated angiographic investigation.

Are brief or recurrent transient global amnesias of epileptic origin?

To evaluate if short (less than one hour) or recurrent, or both, episodes of transient global amnesia (TGA) have an epileptic origin or carry a subsequent risk of epilepsy a group of patients with these types of TGA attacks was studied. The group was selected from a prospective series of 103 patients with TGA. Sixteen patients had an episode lasting less than one hour, 13 had more than one episode, and five patients had both short and recurrent attacks. For each patient the number of recurrences was small (four or less) and they were separated by months or years. During short attacks of TGA many subjects showed other typical features of TGA including repeated questioning (12 subjects) and performance of purposeful complex acts (eight subjects). Twelve short attacks were closely related to a characteristic precipitating event. During follow up only one patient had a seizure (partial motor). No other association between either short or repeated attacks of TGA and past history of epilepsy or paroxysmal discharges were seen on the EEG. Short or recurrent, or both, attacks of TGA are not epileptic and do not carry a relevant risk of subsequent seizures.

Fatal hemorrhage during anticoagulation of cardioembolic infarction: role of cerebral amyloid angiopathy

We report a patient with recurrent cardioembolism and hemorrhagic infarcts, who developed a fatal intracerebral hemorrhage 3 days after intravenous anticoagulation. At autopsy, cerebral amyloid angiopathy (CAA) was found. Because CAA and anticoagulation may add up to trigger cerebral hemorrhage, the possibility of underlying CAA should be raised before anticoagulating elderly patients with stroke.

[Comas in the emergency room of a central hospital]

The aim of the present prospective work was to study the etiologic diagnosis and prognosis of the comatose patients for whom a neurologic examination is requested. It included 148 consecutive cases admitted to the emergency room of a general hospital. Coma was caused by supratentorial lesions in 38%, subtentorial lesions in 10%, diffuse or metabolic brain dysfunction in 49%, and psychiatric disorder in 1% of the patients. CT scan was the most valuable ancillary exam, modifying the initial etiologic diagnosis in 42% of the cases on whom it was performed. Seventy percent of the patients died. Coma caused by structural lesions had a worse outcome than coma caused by diffuse or metabolic brain dysfunction (intoxications excluded), and this type of coma had a worse outcome than drug-induced coma. The presence of anisocoria, the number of brainstem reflexes present and the pattern of motor response, as well as the Glasgow Coma Scale score, predicted the outcome.

Thalamic ataxia

Seventeen patients with hemiataxia as a manifestation of thalamic infarction were studied. Hemiataxia had the main clinical characteristics of a "cerebellar type" of ataxia, though it never occurred in isolation, being associated with ipsilateral sensory disturbance (hemiataxia-hypaesthesia) in 7 patients, with ipsilateral sensory disturbance and hemiparesis (hypaesthetic ataxic hemiparesis) in 8 patients, and with hemiparesis (ataxic hemiparesis) in 2 patients. Recovery was good, and in all patients the sensory and motor disturbances improved or cleared before the hemiataxia. All patients had an infarct involving the lateral part of the thalamus (thalamogeniculate territory in 16, tuberothalamic territory in 1), also affecting the posterior limb of the internal capsule (PLIC) in 7 patients. Hemiataxia seemed linked to involvement of the caudal part of the ventral lateral nucleus of the thalamus or the immediately adjacent medial part of the PLIC. These structures are near the corticospinal pathways and the ventral posterior nucleus of the thalamus, explaining why hemiataxia is associated with hemiparesis or hypaesthesia in this type of infarct.

Hemiataxia-hypesthesia: a thalamic stroke syndrome

Six patients had isolated hemiataxia and ipsilateral sensory loss, as a manifestation of thalamic infarction in the thalamogeniculate territory. Acute hemiataxia-hypesthesia was not found in 1075 other patients from the Lausanne Stroke Registry who were admitted during the same period. Stroke onset was progressive in five patients and immediately complete in one. Five patients had an objective sensory loss. In two patients this affected light touch, pain and temperature sense, and in another three light touch, pain temperature, position and vibration sense. One patient had a purely subjective sensory disturbance. The sensory deficit cleared or was clearing although the ataxia persisted in all patients. On lesion mapping on CT or MRI, all patients had involvement of the lateral part of the thalamus (ventral posterior nucleus and ventral lateral nucleus). The presumed causes of stroke were cardioembolism in one patient, posterior cerebral artery occlusion in one patient and meningovascular syphilis in one patient, hypertensive small vessel disease in two patients, and undetermined in one patient. Hemiataxia-hypesthesia is a new stroke syndrome involving the perforating branches to the lateral thalamus, but in which small vessel disease may not be the leading cause.

Pure motor stroke: a reappraisal

We studied the correlations between the pattern of weakness, stroke type, topography, and etiology in 255 patients whose first stroke was manifested by isolated hemiparesis. They represented 14% of consecutively admitted stroke patients. The weakness distributions were as follows: face, upper limb, and lower limb (FUL) (50%); face and upper limb (FU) (29%); upper limb (U) (10%); and upper and lower limb (UL) (9%). Twenty-nine percent of the patients had dysarthria, which was of no localizing value. Less than one half of the patients had a deep infarct, and one third had a potential embolic source from the heart or large arteries. Logistic regression analysis showed that history of hypertension and type of weakness distribution were the main factors accounting for lesion localization: patients with FUL distribution and hypertension had a 90% probability of deep infarct; patients either with FUL distribution but no hypertension or with UL distribution and hypertension each had 70% probability of deep infarct. Pure motor monoparesis was almost never caused by a deep infarct. We suggest that the assumption of a lacunar etiology to a pure motor stroke should be applied only to patients with FUL involvement.

Transient global amnesia. A case control study

A case control study of transient global amnesia (TGA), transient ischaemic attacks (TIA) and normal controls is described. Each of the 51 TGA patients, selected between January 1985 and March 1990, was compared with four controls (two TIAs and two normals) for the presence of vascular risk factors (hypertension, diabetes, smoking habits, cholesterol, triglycerides and haematocrit levels, heart disease, previous stroke), previous TGA, migraine, psychiatric illness and recent head trauma. Patients with TGA had less diabetes, hypercholesterolaemia and hypertriglyceridaemia than TIA. TGA subjects had significantly more hypertension (odds ratio = 3.31) and migraine (odds ratio = 8.67) than normal controls. During a mean of 17.4 mths of follow-up (range 1-96 mths), three subjects had recurrent TGA, one sustained a TIA and a minor stroke, but none had seizures. Thrombo-embolism and epilepsy are unlikely to be the cause of this benign disorder. The role is stressed of appropriate precipitants, including haemodynamic changes, and of individual susceptibility (of which migraine is probably a marker) in the genesis of TGA.

[Nimodipine in subarachnoid hemorrhage]

The efficacy of nimodipine in decreasing mortality and morbidity of subarachnoid haemorrhage (HSA) is evaluated in 51 patients admitted to the Neurological and Neurosurgery Departments of the Santa Maria Hospital. Reductions of 2 x (0.65, 6.39) of the incidence of ischemia in the total group and of 2.1 x (0.58, 7.79) of mortality in the sub-group with initial severity of less than 4 points of the Hunt score were observed relatively to a comparable group of patients previously admitted who did not receive nimodipine. Randomized clinical trials that tested the effect of nimodipine in the context of HSA are reviewed.

[The patient with acute cerebrovascular disorders: assessment of associated diseases]

We performed a prospective study in 106 patients with acute stroke. The main purpose was to evaluate the associated diseases and to determine their prevalence and incidence in two different types of cerebrovascular disease: the intracerebral hemorrhage (HI) and ischaemic events (AI). The studied population included 54 men and 52 women with a mean age of 66.8 +/- 10.3 years. A clinical examination was performed in all patients by different specialists and all were submitted to diverse complementary tests, including a computed tomography scan of the brain (TAC) and an echocardiogram (ECO). We found 24 (23%) HI and 82 (77%) AI. In the past history, previous stroke were more prevalent in AI (p less than 0.01). Heart disease was present in 87 (82%) patients but, among them, only atrial fibrillation which was found in 19 (18%) patients, was significantly more frequent in AI (p less than 0.02). Hypertension (HTA) existed in 79 (75%) patients, respiratory complications and periferic vascular disease in 9 (8%), diabetes in 44 (42%) and dyslipidemia in 31 (29%) patients. No significant difference was found between the two groups of stroke regarding these diseases; however, there was a tendency for HTA and diabetes to be more prevalent in HI and for periferic vascular disease in AI. In the blood tests, high haematocrit was found in 35 (33%) patients, anemia in 21 (20%), hypercholesterolemia in 17 (16%), hypertrigliceridemia in 18 (17%) and uremia or creatinemia or ionic alteration in 32 (30%) patients, without any difference in their prevalence and incidence in the two groups of stroke. In conclusion, in this prospective study of patients with an acute stroke, there was 23% of HI and 77% of AI, a high prevalence of previous stroke, heart disease and HTA, but only the previous stroke and, within heart disease, the atrial fibrillation were significantly more frequent in the AI group. Also, periferic vascular disease had a tendency to be more frequent in AI, as well as diabetes and HTA had in HI.

[The importance of heart disease in the various types of cerebral vascular disease. A prospective study]

A prospective study was performed in 106 patients with acute stroke. The main purpose was the cardiac evaluation in the different types of cerebrovascular disease: Intracerebral hemorrhage (H), Cortical ischaemic events (C) and Subcortical ischaemic events (SC) and also to evaluate the interest of echocardiography in detecting occult cardiac sources of emboli. The study population included 54 men and 52 women with a mean age of 66.8 +/- 10.3 years. A thorough neurologic and cardiologic study with a computed tomography of the brain (TAC) and an echocardiogram (ECO) were performed in all patients. It was found 24 (23%) of H, 40 (38%) of C and 32 (30%) of SC. In the past history, heart diseases were more prevalent in C (p less than 0.04); previous stroke and systemic hypertension (HTA) were less prevalent in H (p less than 0.008) and in C (p less than 0.004), respectively. Atrial fibrillation (FA) was more frequent in ischaemic stroke (p less than 0.02) and within these in C (p less than 0.005). No more clinical and functional cardiac features or echocardiographic aspects had any difference in their prevalence in different types of stroke. Without clinical heart disease there were 19 (18%) cases but only in 10 were found in their echocardiograms a potentially embolic heart disease (PEHD) but 8 of them had questionable pathologic significance.

IN CONCLUSION

C had more heart disease in their past history; FA is more frequent in C; it is difficult to diagnose a cerebral embolism with only a coexistent C and CPE, but if there is FA or a past history of heart disease in a C, the diagnosis of cerebral embolism is more probable; finally, echocardiography is of limited value to diagnose a PEHD in the elderly, however it makes possible to better evaluate most cardiac situations.

Autosomal dominant cerebellar ataxia with deafness, myoclonus and amyotrophy

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