Anti-polysaccharide immunoglobulin isotype levels and opsonic activity of antisera: relationships with protection against Streptococcus pneumoniae infection in mice

Relationships between in vitro parameters (opsonic activity and anti-pneumococcal polysaccharide [PS] antibody subclasses) and in vivo mouse protection were established by logistic regression analysis. Data were from 158 mice challenged with pneumococci after vaccination with synthetic oligosaccharide- and PS-protein conjugates in combination with the adjuvant Quil A. The hypothesis that serum opsonic activity has predictive value for protection against pneumococcal infection was tested. Serum opsonic activity was well correlated with protection (chi 2 = 35.5, P < 0.001), although a stronger correlation was observed for anti-PS IgM and IgG. The combined use of IgG and opsonic activity as predictor variables yielded the best fitting model for predicting protection (chi 2 = 74.1, P < 0.001). When opsonic activity data were added to models that included various antibody isotypes, the statistical significance of the models was enhanced. Thus, the opsonic activity of antisera induced by pneumococcal vaccines can predict mouse protection.

Neurobehavioral effects of acute and chronic mixed-solvent exposure in the screen printing industry

This 2-year prospective study examined the neurobehavioral effects of acute and chronic exposure to mixed solvents in workers in a screen printing business. A total of 30 subjects participated in the study in two field testings over a 12 month period. Each subject completed a detailed medical and occupational questionnaire, had a neurological examination, and underwent a battery of neuropsychological tests. Industrial hygiene investigation identified the following chemical exposures as present: toluene, methyl ethyl ketone, mineral spirits, beta-ether, methylene chloride, and acetic acid. Different departments and jobs had varying degrees of exposure to these chemicals, the highest exposures being in the ink mix area and the screen washroom area. However, all exposure levels were below recommended threshold limit values. Persons categorized as having higher acute exposure demonstrated significantly impaired test performance on tasks involving manual dexterity, visual memory, and mood. Those with higher chronic exposure demonstrated significantly poorer performance on visual memory tasks and mood. Results suggest that the mixed solvents used in the screen printing industry have an effect on central nervous system functioning in the absence of obvious clinical disease.

Human immunoglobulin G (IgG) Fc receptor IIA (CD32) polymorphism and IgG2-mediated bacterial phagocytosis by neutrophils

Human immunoglobulin G (IgG) Fc receptor IIa (Fc gamma RIIa; CD32) is expressed on phagocytes, triggers phagocytosis, and represents the sole Fc receptor for IgG (Fc gamma R) capable of interaction with IgG2, the main IgG subclass induced in response to bacterial capsular polysaccharides. The two genetically determined structurally different allotypes of human Fc gamma RIIa, the products of the Fc gamma RIIa-R131 and IIa-H131 alleles, have functionally different reactivities with human IgG2. In humans, the Fc gamma RIIa-H131 allotype is known to interact efficiently with complexed human IgG2, whereas the IIa-H131 allotype does so only poorly. This polymorphism may therefore have implications for IgG2-mediated phagocytosis of encapsulated bacteria and susceptibility to bacterial infections. Phagocytosis of IgG2-opsonized bacteria by homozygous Fc gamma RIIa-R/R131, heterozygous IIa-H/R131, and homozygous IIa-H/H131 polymorphonuclear cells (PMN) was compared. A higher phagocytic capacity of IgG2-opsonized group B type III streptococci by PMN of homozygous H/H131 individuals compared with PMN from homozygous R/R131 individuals was observed (P = 0.001), while heterozygous IIa-H/R131 PMN showed intermediate phagocytosis. In this model system, IgG2-mediated phagocytosis was independent of the Fc gamma RIIIb-NA1/NA2 allelic polymorphism.

Solid-phase antigen density and avidity of antibodies detected in anti-group B streptococcal type III IgG enzyme immunoassays

Two enzyme immunoassays which measure anti-group B streptococcal type III capsular carbohydrate IgG antibodies were compared. One utilised poly-L-lysine conjugated coating antigen while the other used tyraminated coating antigen. Both carbohydrate antigens appeared to be antigenically identical but the poly-L-lysine based assay gave significantly lower values for some sera. Sera were identified which had low and high avidity anti-group B streptococcal type III IgG antibodies by the thiocyanate elution method. These antibodies gave results on a dilution range of coating concentrations consistent with their relative avidity. Comparison of dilution ranges of the two conjugates used for coating suggests that the poly-L-lysine conjugate coats with a ten-fold lower efficiency than the tyramine conjugate and therefore detects only higher avidity antibodies. Four fractions containing different relative avidities of affinity-purified IgG were produced from a single serum. These fractions behaved in the same manner as sera containing antibodies of different avidities. The results of this study suggest that the method of polysaccharide conjugation in enzyme immunoassays may affect the antigen concentration on the solid phase and thence the detection of antibodies of various avidities.

Epitope specificity of rabbit immunoglobulin G (IgG) elicited by pneumococcal type 23F synthetic oligosaccharide- and native polysaccharide-protein conjugate vaccines: comparison with human anti-polysaccharide 23F IgG

Streptococcus pneumoniae type 23F capsular polysaccharide (PS23F) consitss of a repeating glycerol-phosphorylated branched tetrasaccharide. The immunogenicities of the following related antigens were investigated: (i) a synthetic trisaccharide comprising the backbone of one repeating unit, (ii) a synthetic tetrasaccharide comprising the complete repeating unit, and (iii) native PS23F (all three conjugated to keyhole limpet hemocyanin [KLH]) and (iv) formalin-killed S. pneumoniae 23F. All antigens except the trisaccharide-KLH conjugate induced relatively high anti-PS23F antibody levels in rabbits. The epitope specificity of such antibodies was then studied by means of an inhibition immunoassay. The alpha(1-->2)-linked L-rhamnose branch was shown to be immunodominant for immunoglobulin G (IgG) induced by tetrasaccharide-KLH, PS23F-KLH, and killed S. pneumoniae 23F: in most sera L-rhamnose totally inhibited the binding of IgG to PS23F. Thus, there appears to be no major difference in epitope specificity between IgG induced by tetrasaccharide-KLH and that induced by antigens containing the polymeric form of PS23F. Human anti-PS23F IgG (either vaccine induced or naturally acquired) had a different epitope specificity: none of the inhibitors used, including L-rhamnose and tetrasaccharide-KLH, exhibited substantial inhibition. These observations suggest that the epitope recognized by human IgG on PS23F is larger than the epitope recognized by rabbit IgG. Both human and rabbit antisera efficiently opsonized type 23F pneumococci, as measured in a phagocytosis assay using human polymorphonuclear leukocytes.

Trimethyltin encephalopathy

A chemistry student was acutely exposed to vapors of an organotin compound. Seventy-two hours later, he exhibited delirium, spatial disorientation, perseveration, inappropriate affect, and memory defects. Five months later, he experienced episodes of complex partial seizures, which continue to require anticonvulsant medication after 7 years. Trimethyltin was identified in blood and urine samples taken 17 days after the accident; the blood level of trimethyltin was elevated 35 days after exposure. Serial electroencephalograms showed persistent left temporal paroxysmal epileptogenic potentials. Serial neuropsychological tests revealed persistent memory defects, cognitive dysfunction, and dysphoria 4 years after exposure. We review acute, resolving, and long-term residual neurotoxic effects of trimethyltin in man. We describe detailed clinical observations, serial neuropsychological test results, electroencephalographic findings, and exposure data in this patient, confirming the limbic system effects of trimethyltin and relating them to the known histopathologic pattern of this condition.

Magnetic resonance imaging (MRI), neurobehavioral testing, and toxic encephalopathy: two cases

The objective of this investigation was to examine cerebral magnetic resonance imaging (MRI) pathology and functional deficits demonstrated by neuropsychological testing in cases of toxic encephalopathy. Two subjects, occupationally exposed to toxic chemicals, were studied. As part of their neurological assessment, MRI was done and each underwent a neuropsychological battery for patients with toxic exposures (White et al. Clin. Neuropharmacol. 13(5), 392-412, 1990). In Case 1, who was exposed to inorganic mercury, MRI showed mild central and cortical atrophy. Punctiform foci (T2) were noted in both frontal regions underlying the precentral gyri and in the subcortical myelin. Neuropsychological testing showed problems in cognitive flexibility, cognitive tracking, inhibiting perseveration, fine manual motor coordination, visuospatial analysis and organization, memory, and affect and personality. In Case 2, who was exposed to 2.6-dimethyl-4-heptanone, MRI showed multiple small foci in the white matter and pons. Neuropsychological testing indicated affective changes, deficits in manual motor speed, verbal fluency, visuospatial organization, and short-term memory. Lack of aphasia in patients with toxic encephalopathy indicates that neurotoxins probably affect subcortical and mesial temporal structures more than cortical gray matter. These MRI studies show subcortical sites of pathology.

Human B lymphocyte in vitro response to the group B streptococcal type III capsular carbohydrate

Anti-group B streptococcal type III polysaccharide-specific human B cells from the peripheral circulation can be activated and detected in an in vitro culture system. It is possible to detect both IgM- and IgG- producing cells from both seropositive and seronegative donors. The specificity of the response was demonstrated by inhibition with excess liquid phase antigen and the use of related but antigenically distinct control antigens. The response was absent without the addition of T cells, optimal at 10% and 25% T cells respectively for IgM- and IgG-secreting cells, and undetectable using 50% T cells. The optimal antigen concentration for in vitro B-cell activation is 2.5 x 10(-4) micrograms/ml. Cells from 5 of 6 seropositive donors and 3 of 7 seronegative donors produced specific IgM antibody after culture with antigen. We conclude that the control of the human antibody response to the group B streptococcal type III polysaccharide is influenced by T cells. The response seen in the culture system may be of value in assessing future vaccine candidates designed to prevent neonatal infections.

Age influences magnitude but not duration of response to levodopa

Following an all-night fast, 45 patients with Parkinson's disease were examined using certain motor items present in the United Parkinson's Disease Rating Scale. All were given a single tablet of carbidopa 25 mg and levodopa 250 mg and re-examined 90 minutes later. In addition to this evaluation, 23 of these patients underwent further scoring over a 4-hour period. A significant negative correlation was found between age and one important aspect of drug-derived benefit: magnitude of response. In contrast, age had no apparent influence on duration of benefit from the drug. Although baseline (fasting) scores were predictably correlated with duration of disease, magnitude of response was not adversely influenced by this variable. Not all Parkinsonian signs were equally influenced by age. Whereas the poor response of gait and bradykinesia appeared to be dependent on age, no such effect was noted on rest tremor scores. The data indicate that in patients with Parkinson's disease treated long term, factors associated with age rather than duration of disease may have a stronger adverse influence on magnitude of response to levodopa.

Lead neurotoxicity and disorders of learning

Preventable and treatable causes of disorders of learning caused by lead exposure can be recognized by heightened awareness of this potential hazard. The Centers for Disease Control using data from many studies of neurobehavioral effects of lead in children and animals, has redefined the lead exposure threshold for clinical and social intervention from 25 micrograms/dL to 10 micrograms/dL. This article reviews the pertinent studies that provide evidence of the effects of lead exposure on development of the nervous system, effects on neural structures involved in memory and learning, and the impact of early lead encephalopathy on adolescent and adult learning skills and cognitive performance. Physicians, teachers, and child care personnel are responsible for identifying children with behavioral signs of subclinical lead intoxication as early as possible. Screening programs and preventive strategies, such as the multitier Centers for Disease Control approach referred to in this article, are necessary. It is no longer reasonable to assume that lead-exposure children not demonstrating severe encephalopathy will recover completely, without residual brain damage after removal from exposure. Sufficient evidence now exists to clearly demonstrate measurable effects of low levels of lead body burden on behavioral and intellectual performance, resulting in learning disorders.

Blink reflex measurement of effects of trichloroethylene exposure on the trigeminal nerve

Trichloroethylene (TCE) exposure is known to have specific toxic effects on cranial nerves, the trigeminal nerve (V) in particular. The electrophysiological measurement of the blink reflex (BR) can quantify latency changes in the Vth and VIIth cranial nerve reflex arc. Prior study looked at the blink reflex measurement in a community group exposed to TCE in their drinking water. This study evaluated the use of the electrophysiologic blink reflex as an indicator of neurotoxic effects of TCE in occupationally exposed workers. The BR was tested in individual cases with documented histories of exposure to known chemical neurotoxins including TCE (n = 18). When compared with the nonexposed laboratory control values (n = 30), the subjects with a significant history of TCE exposure demonstrated the most prolonged latencies (greater than or equal to 3.0 SD above the nonexposed group mean) in the R1 component of the blink reflex measurement. The electrophysiological study of the blink reflex has application in assessing TCE exposure and in documenting the neurotoxic effects of that exposure on trigeminal nerve functions in humans.

Abnormalities in color vision and contrast sensitivity in Parkinson's disease

Dopamine is a neurotransmitter found in the retina. Delays in the visual evoked responses and abnormalities in contrast sensitivity occur in patients with Parkinson's disease. Improvement in the P100 has followed L-dopa therapy. Suspected abnormalities at the retinal level in Parkinson's disease are observed in reductions in photopic, scotopic, and pattern-derived electroretinograms. We studied 35 patients with Parkinson's disease and 26 controls of comparable age and visual acuities using visual evoked responses, color vision, and contrast sensitivity testing. Contrast sensitivity thresholds were significantly different at most frequencies tested, using both stationary and temporally modulated sinusoidal gratings. The total error score of the Farnsworth-Munsell 100 Hue Test revealed significant differences between the patients and controls. The contrast thresholds derived from certain spatial frequencies and the total error in color score were significantly related to the duration of disease. A stepwise discriminant analysis correctly identified 94% of the patients and 94% of the controls. The significant error in chromatic discrimination observed in Parkinson's disease patients may be due to altered intraretinal dopaminergic synaptic activity in these patients.

A perceived cluster of amyotrophic lateral sclerosis cases in a Massachusetts community

We investigated a report of a perceived cluster of amyotrophic lateral sclerosis (ALS) in Middleborough, Mass. Although an increase in ALS incidence was observed [2.51 deaths/100,000 person-years (p-y)], relative to the statewide rate over the years 1969-1985 (1.26/100,000 p-y), it was not statistically significant at the 95% confidence level. Problems in evaluating possible neurological disease clusters and their association with environmental exposures are presented.

Hippocampal lesions in dominantly inherited Alzheimer's disease

We compared hippocampal lesions in three pedigrees of Familial Alzheimer's Disease (FAD). In these pedigrees, the disease is inherited as an autosomal dominant disorder and has been linked to DNA markers on chromosome 21. In eight cases of FAD (four from one pedigree and two each from two others) we quantified neurofibrillary tangles (NFT) and senile plaques (SP) in hippocampal subdivision CA1-4, subiculum, presubiculum, and dentate gyrus. We observed consistent patterns of the distribution of lesions: The highest density of NFT and SP was present in CA1-2; virtually no SP or NFT were present in presubiculum; SP diameter was consistently greatest in CA4. We found no overall differences among pedigrees in total densities of NFT and SP, but statistical analyses disclosed that an uncommon type of SP was disproportionately present in two pedigrees. This type of SP was usually restricted to CA4, had a marked amyloid core devoid of argyrophilic neurites. These studies also disclosed inter- and intrafamilial heterogeneity of lesion distribution (including congophilic angiopathy and cerebellar plaques) in these three pedigrees.

Prevalence of anti-group B streptococcal type III capsular IgG antibodies in the United Kingdom and an analysis of their specific IgG subclasses

Neonatal infection due to group B streptococcus (GBS) has a higher incidence in the USA than in the United Kingdom. A British population was investigated to ascertain the proportion of women who have protective anti-GBS type III IgG levels. Thirty-one (34%) of 90 pregnant women, 10 (43%) of 23 nonpregnant women, and 5 (50%) of 10 mothers of healthy colonized infants had anti-type III IgG greater than or equal to 2 micrograms/ml. Of 19 mothers who had infants infected with GBS type III, 17 (89%) had low specific IgG levels; of the other 2, the infants themselves had low IgG levels. The proportion of women in the UK with protective antibody levels is higher than in the USA. Sera (12) were assayed for anti-type III IgG isotypes; all contained IgG2, 6 had detectable IgG1, and 1 had IgG4.

Immunoglobulin prophylaxis for infants exposed to varicella in a neonatal unit

The investigation and prophylaxis with anti-varicella-zoster immunoglobulin (ZIG) of 15 preterm infants (24-33 weeks gestation and 1-300 days postnatal age) exposed to varicella on a neonatal intensive care unit are described. Varicella-zoster virus (VZV) IgG was detectable in 13 infants (24-28 weeks gestation) less than 105 days of age and born to seropositive mothers. Current guidelines recommend ZIG for all preterm infants of less than 28 weeks gestation following exposure to VZV. Our findings suggest that ZIG need be given only to seronegative infants or infants of seronegative mothers and to those over 60 days postnatal age.

Relation of distribution of conduction velocities to nerve biopsy findings in n-hexane poisoning

Distribution of conduction velocities (DCV) of sensory fibers in sural nerve was investigated in three patients with n-hexane poisoning. Measurements were made at 1-2 months, 4-9 months, and at 11, 23, and 36 months after ending exposure. A sural nerve biopsy was obtained from one of the patients. The results indicated the characteristic changes of n-hexane toxicity: myelinated nerve fiber degeneration and paranodal swelling, resulting in changes in the fiber diameter distribution. The DCV documented these changes. After removal from toxic exposure, varying degrees of recovery were studied clinically and evaluated with nerve conduction parameters. The DCV reflects the pathological changes in nerve in toxic neuropathy due to n-hexane.

Environmentally related disorders of the nervous system

Specific physical and chemical agents found in the workplace and in the general environment are responsible for characteristic pathologic processes within the nervous system. It has been shown that many neurotoxic agents produce a dose-related spectrum of impairment ranging from mild slowing of nerve conducting velocity or prolongation in reaction time to neuropathy and frank encephalopathy. Clinical manifestations are determined by the agent involved, by the dose of exposure, the vulnerability of the cellular target, the ability of the organism to metabolize and excrete the agent, and the ability to repair damage. An occupational history, including evaluation of evidence of specific agents and job history, is a critical component in the clinical management of individuals with suspect neurotoxic disease. Environmentally-induced disorders can be prevented by appropriate environmental controls. Prevention of neurotoxic disease is a complex process requiring continuous involvement of public health agencies and strong scientific research.

Double-blind comparison of standard Sinemet and Sinemet CR in patients with mild-to-moderate Parkinson's disease

The combination of carbidopa and levodopa (Sinemet) is a highly effective treatment for the symptoms of Parkinson's disease. However, side effects, such as abnormal involuntary movements, fluctuations in motor performance, and "wearing off" phenomena limit its long-term usefulness in some patients. Open-label studies show that controlled-release Sinemet CR is effective in reducing motor fluctuations. This report discusses the results of a 14-week double-blind crossover study comparing the efficacy and tolerability of standard Sinemet with controlled-release Sinemet CR. Overall, there were no statistically significant differences in efficacy between Sinemet CR and standard Sinemet on any of the major efficacy measures, suggesting a clinical equivalence in terms of treating the symptoms of Parkinson's disease. The study also supports the tolerability of Sinemet CR. In summary, Sinemet CR holds the promise of reducing some disturbing side effects of long-term levodopa therapy, thus achieving optimal control of parkinsonian symptoms.

Magnitude of response to levodopa in Parkinson disease as it relates to peripheral and central measurements of levodopa and associated metabolites

The relationships between magnitude of response to orally administered carbidopa/levodopa (CD/LD) and serum/cerebrospinal fluid (CSF) concentrations of levodopa (LD), 3-O-methyldopa (3-O-MD), and homovanillic acid (HVA) were studied in 15 patients with chronic LD-treated Parkinson disease. The degree of clinical benefit derived from a 25/250 tablet of CD/LD could not be correlated with absolute serum levels of LD, 3-O-MD or LD/3-O-MD ratios. CSF levels of LD and 3-O-MD were also not associated with improvement. CSF levels of HVA, however, did significantly correlate with magnitude of response to LD. Furthermore, CSF HVA levels were not dependent on previous LD dosage. Our data suggest that in chronic LD-treated patients, central factors related to the integrity of the nigrostriatal tract may be a more important determinant of magnitude of response to LD than peripheral elements affecting the amount of LD entering the central nervous system.

Neurologic considerations in worker fitness evaluation

This chapter focuses on neurological conditions that may seriously change work performance or risk, as well as considerations in neurological evaluation of the asymptomatic worker.

Blink reflex latency after exposure to trichloroethylene in well water

The electrophysiological measurement of the blink reflex (BR) can quantify the conduction latency in the reflex arc involving the Vth (trigeminal) and VIIth (facial) cranial nerves. We measured the electrophysiological BR in a population (N = 21), which had alleged chronic exposure to trichloroethylene (TCE) through the public drinking water at levels 30-80 times higher than the Environmental Protection Agency (EPA) Maximum Contamination Level (MCL). A highly significant difference was observed in the conduction latency means of the BR components (p less than .0001), when the study population was compared with laboratory controls (N = 27). This difference suggests a subclinical alteration of the Vth cranial nerve function due to chronic, environmental exposure to TCE.

Database handling for infection control and hospital epidemiology

In 1977 the Department of Microbiology, University College Hospital, London introduced an integrated data processing system. The system was designed primarily to produce individual reports on specimens processed. Input was via visual display units (VDU's) using nmemonic codes. Additionally data is sorted by the software to provide daily, weekly, monthly and annual listings for epidemiological use. Listings concerning specific problem area can be produced as required. As computing power and data storage systems become cheaper it should be possible to improve upon the quality of epidemiological information available. A continuous surveillance system is envisaged where each day all potential outbreaks are displayed and help with their management is offered. Information on incidence of infections and changing trends (such as anti-microbial resistance patterns) would be instantly available in numerical and graphical form. Modern colour VDU's and new programming techniques would make the system especially easy to use by the untrained operator.

Effects of castration on peritoneal fluid in the horse

Twenty-four clinically normal horses were castrated by routine methods. Peritoneal fluid was collected prior to castration and at 1, 3, 5, and 7 days postcastration. Peritoneal fluid was collected on days 9 and 11 if nucleated cell (NC) counts were still markedly elevated on day 7. Peritonitis, defined as NC counts greater than 10,000/microliters, was evident in 15 horses following castration. Mean NC counts peaked on day 5 but were less than 10,000/microliters for 74% of the horses by day 7, and 90% of the horses by day 9. One horse had a NC count greater than 60,000/microliters on day 11 when sampling ended. Postcastration peritoneal fluid was obviously blood-tinged in 21 horses. Peak RBC counts occurred on day 3 but markedly decreased by day 5. Elevated peritoneal RBC counts correlated well with elevated NC counts (P less than 0.001). Horses with peritonitis tended to have fever (P less than 0.05). Other clinical signs of peritonitis were not apparent.

Threshold effect in lead-induced peripheral neuropathy

We previously demonstrated a negative correlation between blood lead level and motor nerve conduction velocity in 202 asymptomatic 5 to 9-year-old children living near a lead smelter in Idaho. Blood lead levels ranged from 13 to 97 micrograms/dL. To determine whether a threshold exists between blood lead level and maximal motor nerve conduction velocity, we conducted three regression analyses on these data: a "hockey stick" regression, a logistic regression, and a quadratic regression. We found evidence for a threshold in all three analyses: at a blood level of 30 micrograms/dL in the "hockey stick" regression, at 20 micrograms/dL in the logistic, and at 25 to 30 micrograms/dL in the quadratic. Neither age, sex, socioeconomic status, nor duration of residence near the smelter significantly modified the relationship. These analyses confirm that asymptomatic increased lead absorption causes slowing of nerve conduction, but they also indicate that measurement of maximal motor nerve conduction velocity is an insensitive screen for low-level lead toxicity.

Risk assessment in electronic assembly workers: carpal tunnel syndrome

Symptoms that develop in workers after repeated mechanical injury may be overlooked until the disability affects their productivity and safety. Modifications in the design of hand-operated tools or adaptations in production ergonomics may prevent further damage and permit affected workers to recover while avoiding the development of repetitive cumulative trauma in workers who are new to the job task. This article describes the results of an on-site survey, a biomechanical analysis, and a special neurologic assessment in an electronic assembly plant and provides a structured approach to worker surveillance and intervention to reduce the risk of carpal tunnel syndrome caused by repetitive motions.

A novel presentation of Coxsackie B2 virus infection during pregnancy

A 39-year-old woman presented at 34 weeks gestation with a febrile illness. This initially settled but recurred 6 days later, when uncontrolled vaginal bleeding necessitated caesarian section. At operation, vesicles were seen on the mother's hyperaemic uterus. The infant developed tachypnoea, bradycardia, cerebral irritation, an enlarged liver and spleen, intravascular coagulation and a transient rash. Mother and child made a full recovery. Coxsackie B2 virus was isolated from the infant and rises in the titre of Coxsackie B virus-specific IgM were detected in mother and child.

Dominantly inherited Alzheimer's disease: cerebral glucose metabolism

Cerebral glucose metabolic rate (CMRGlu), measured by positron emission tomography, was bilaterally and symmetrically reduced in two patients with autosomal dominant Alzheimer's disease. Supramarginal gyri and temporal lobes were most severely affected. An isolated reduction of CMRGlu in the left supramarginal gyrus was observed in one asymptomatic at-risk subject.

Delayed visual evoked potentials are independent of pattern orientation in macular disease

Visual evoked potentials (VEPs) and contrast sensitivity (CS) were studied in patients affected by maculopathy. VEP delays and CS reduction were demonstrated in each affected eye. In distinction to patients affected by multiple sclerosis (MS), in maculopathy patients VEP latency is independent of the orientation of the grating stimulus. It is proposed that stimulating with more than one pattern orientation is useful in the differential diagnostic use of VEPs.

The genetic defect causing familial Alzheimer's disease maps on chromosome 21

Alzheimer's disease is a leading cause of morbidity and mortality among the elderly. Several families have been described in which Alzheimer's disease is caused by an autosomal dominant gene defect. The chromosomal location of this defective gene has been discovered by using genetic linkage to DNA markers on chromosome 21. The localization on chromosome 21 provides an explanation for the occurrence of Alzheimer's disease-like pathology in Down syndrome. Isolation and characterization of the gene at this locus may yield new insights into the nature of the defect causing familial Alzheimer's disease and possibly, into the etiology of all forms of Alzheimer's disease.

Occupational neurology

The nervous system is vulnerable to the effects of certain chemicals and physical conditions found in the work environment. The activities of an occupational neurologist focus on the evaluation of patients with neurological disorders caused by occupational or environmental conditions. When one is making a differential diagnosis in patients with neurological disorders, the possibility of toxic exposure or encounters with physical factors in the workplace must not be overlooked. Central to an accurate clinical diagnosis is the patient's history. A diagnosis of an occupational or environmental neurological problem requires a careful assessment of the clinical abnormalities and confirmation of these disabilities by objective tests such as nerve conduction velocity, evoked potentials, electroencephalogram, neuropsychological batteries, or nerve biopsy. On the basis of information about hazards in the workplace, safety standards and environmental and biological monitoring can be implemented in the workplace to reduce the risks of undue injury. Clinical manifestations of headache, memory disturbance, and peripheral neuropathy are commonly encountered presentations of the effects of occupational hazards. Physicians in everyday clinical practice must be aware of the signs and symptoms associated with exposure to possible neurotoxins and work methods. Occupational and environmental circumstances must be explored when evaluating patients with neurologic disorders.

Parkinson's disease: follow-up after "drug holiday"

Long-term management of patients with Parkinson's disease includes close monitoring and frequent dose adjustment. In a small selected group of patients, complete withdrawal of L-dopa (drug holiday) and slow reintroduction of lower doses of this drug assured continued benefit for six to 24 months. We studied 45 drug holidays in 45 patients with idiopathic Parkinson's disease. Average preholiday L-dopa dose was 2,970 mg/d; at 24 months, it was 263 mg/d. The drug holiday resulted in reduced adverse drug effects (dyskinesias, "on-off" phenomenon, hallucinations, and confusion), and improved functional ratings at one, six, 12, and 24 months after the drug holiday.

Neurological aspects of mycoplasmal infection

Mycoplasmal infections may be complicated by a wide variety of systemic syndromes, including neurological disorders. Circumstantial evidence suggests that these are immunologically-induced. A detailed study of five patients with proven mycoplasma pneumoniae and central nervous system signs showed that immunological factors were involved and suggested that the neurological symptoms were due to a vasculopathy.

Aetiology of urinary symptoms in sexually active women

Two hundred and fifty six unselected women, 50 of whom had urinary symptoms (frequency of urination or dysuria, or both), and who were attending a department of genitourinary medicine, were investigated. The urinary symptoms were associated both with pyuria and the isolation of undoubted pathogens from midstream urine (MSU) specimens. No associations were found between urinary symptoms and the isolation of Neisseria gonorrhoeae or Chlamydia trachomatis from the urethra or cervix; the recovery of Mycoplasma hominis from the urethra, cervix, or MSU; the recovery of Trichomonas vaginalis or Candida albicans from the vagina; or the presence of bacterial vaginosis. Urethral leucocytosis was associated with the isolation of T vaginalis but not with the recovery of N gonorrhoeae, C trachomatis, C albicans, or urinary pathogens. Pyuria was associated with the isolation of urinary pathogens and with the presence of trichomoniasis; it was not associated with the recovery of C trachomatis or M hominis.

Detection of group B streptococcal antigen in necropsy specimens using monoclonal antibody and immunoperoxidase staining

A murine monoclonal antibody, which recognises various serotypes of group B Streptococcus in formalin fixed, paraffin embedded tissue, was used to show the organism in necropsy specimens of newborn infant lung by an indirect immunoperoxidase technique. The method seemed to be complementary to that of Gram staining, and may be successfully used to identify group B Streptococcus antigen in histopathological material.