Long-term survival of people with unprovoked seizures: a population-based study

PURPOSE

Few population-based studies of long-term survival in people with seizures or epilepsy have been made.

METHODS

Between January 1, 1960 and December 31, 1964, we identified 224 incidence cases of unprovoked seizures in Iceland and determined survivorship status and date of death for the cases as of January 1, 1996. We compared survivorship with that expected based on data from age-/sex-specific life tables from the country for 1961-1990 and calculated the standardized mortality ratio (SMR).

RESULTS

By 30 years after diagnosis, there were 45 deaths among patients with unprovoked seizures as compared with an expected 28 deaths [standardized mortality ratio (SMR) 1.6; 95% confidence interval (CI) 1.2-2.2]. Patients with unprovoked seizures of unknown etiology did not have a significant increase in mortality overall (SMR 1.3, 95% CI 0.8-1.9) or in any time interval. For patients with remote symptomatic unprovoked seizures, mortality was increased (SMR 2.3, 95% CI 1.4-3.5). This increase was attributable to excess mortality for the first 15 years after diagnosis (SMR 4.1, 95% CI 2.4-6.6), and SMR was not different after that time.

CONCLUSIONS

Survivorship was decreased for the population of patients with unprovoked seizures. The increased mortality was primarily due to excess mortality in patients with remote symptomatic seizures, occurring in the first 15 years after diagnosis. Overall mortality for idiopathic unprovoked seizures was not significantly increased.

[Epidemiological study on cognitive abilities in the elderly in two separate rural areas in Iceland.]

OBJECTIVES

This study was undertaken to estimate the cognitive abilities in an elderly population in rural areas in Iceland and to get an idea of the prevalence of dementia. By examining inhabitants in two different areas it was further possible to detect any possible difference in these areas.

MATERIAL AND METHODS

All persons aged 70 and over, living independently in the community and in institutions in two geographically separate areas were contacted. The areas were an agricultural (area A) and a fishing (area F) one. Four simple neuropsychological tests where used, the MMSE (Mini Mental State Examination), WAIS (Wechsler Adult Intelligence Scale)-Similarities, Trail making test A and Trail making test B. Two students in psychology and a teacher were trained in applying the tests but the results were scored and interpreted by the authors.

RESULTS

In area A, 280 of 353 (79.3%) participated and in area F, 190 of 238 (79.8%). Participation was thus similar in both areas. There was a highly significant difference in all the tests with p<0.01 in Trail making test B but p<0.001 in the other three tests. In all the tests the results were better among the population in area A. The prevalence of dementia as estimated by the MMSE showed a prevalence of 14.4% in area A and 35.7% in area F.

CONCLUSION

A significant difference in cognitive abilities was found between the elderly inhabitants of two separate rural areas in Iceland. There is substantial evidence to suggest that this difference is real but it is however not clear if the prevalence of dementia is higher in this study than in others. It is postulated that the difference found is due to cultural differences.

Long-term follow-up after methyl chloride intoxication

In this study, the authors investigated mortality and cancer patterns among a group of individuals accidentally exposed to methyl chloride 32 y earlier. This group of 24 persons had survived the immediate intoxication, which had occurred on a trawler during a fishing trip. The authors selected a reference group, which contained five times as many individuals as the study group, from registers of crews, and they controlled for age, occupation, social class, and lifestyle factors. The authors established a record linkage through personal identification numbers with the national death register and cancer register, thus securing 100% follow-up. The Mantel-Haenszel point estimate (M-H) was 2.2, and the 95% confidence interval (CI) was 1.3-3.1 for all causes of death. There was an excess of deaths from cardiovascular diseases (M-H = 2.1, 95% CI = 1.2-3.8). This excess mortality was more prominent among deckhands who had been subject to higher exposure; risk ratios (RRs) were elevated for all causes of death (RR = 2.5, 95% CI = 1.0-5.7), as well as for cardiovascular diseases (RR = 3.9, 95% CI = 1.0-14.4). In addition, the authors noted elevated risks for all cancers (M-H = 1.5, 95% CI = 0.3-5.6) and for lung cancer (M-H = 2.7, 95% CI = 0.1-52.6). The authors concluded that exposure to methyl chloride may have contributed to the risk of cardiovascular disease. Investigators need to conduct further studies on groups exposed to methyl chloride to refute or confirm this result.

Spirometric values in obese individuals. Effects of body position

Obesity is increasingly prevalent. Earlier studies indicated that there was a significant but small difference in spirometric values between sitting and standing position in the normal population. It is not known if this is true for obese individuals. The recommendations of the American Thoracic Society (ATS) are to document if a spirometry is done in a sitting or standing position. We performed a study in which we compared sitting and standing spirometric values in obese individuals. Patients with a body mass index (BMI) > or = 30 kg/m2 who were referred for spirometry were invited to participate. All tests were done according to American Thoracic Society recommendations. We studied 50 subjects (32 females and 18 males; mean age 45 yr [SD +/- 14.4]). Age range was 20-71 years. Average BMI was 39 (SD +/- 7, range 30 to 65). Twenty-two did the first testing in the sitting position and 28 standing. There was a small but statistically significant difference between forced vital capacity (FVC) in the standing versus sitting position (Wilcoxen test, p < or = 0.05). There was no significant difference in FEV1 between sitting and standing. Our conclusion is that body position is not important when performing spirometry in persons with BMI > or = 30 kg/m2.

Interferon-gamma is necessary for the expression of hypersensitivity pneumonitis

Farmers lung disease is a common form of hypersensitivity pneumonitis (HP) and is characterized by inflammation and granuloma formation in the lung. Interferon-gamma is important for the expression of granulomatous diseases caused by infectious agents; however, the role this mediator in regulating expression of the granulomatous response to inhaled antigen is not known. To evaluate this, we compared the response to inhaled antigen of mice that do not express the gene coding for interferon-gamma (GKO) with that of their normal littermates (WT). GKO and WT mice on a BALB/c background were exposed to 150 microg of the thermophilic bacteria Saccharopolyspora rectivirgula or saline alone, for three consecutive days a week, for 3 wk. After exposure to antigen, WT mice developed a marked granulomatous inflammation associated with an increase in lung weight and numbers of cells in bronchoalveolar lavage fluid (BAL). Although GKO mice also exhibited an increase in lung weight and numbers of cells in BAL fluid, they developed minimal inflammation and no granulomas after a similar exposure to antigen. To further evaluate if the lack of a response to antigen in GKO mice was due to lack of IFN-gamma, we replaced this mediator via intraperitoneal injections. When given replacement IFN-gamma, the GKO mice developed granulomatous inflammation in the lung. These studies show that IFN-gamma is essential for the expression of hypersensitivity pneumonitis.

A population-based study of prognosis of ruptured cerebral aneurysm: mortality and recurrence of subarachnoid hemorrhage

OBJECTIVE

To determine the risk of recurrent subarachnoid hemorrhage (SAH), mortality, and relative survivorship following SAH caused by ruptured cerebral aneurysm (RCA).

DESIGN/METHODS

The 86 individuals with a first diagnosis of SAH caused by RCA in Iceland from 1958 through 1968 were followed a minimum of 24 years (range, 24 to 32.5 years) or until death to determine mortality and to identify those with recurrent SAH.

RESULTS

Thirty-eight patients (44%) died within 30 days of the index event. Two additional (both comatose from onset of ictus) died in the following month. There were no deaths between 3 and 6 months after onset. Based upon the age/gender-specific person years of observation for the population of Iceland, the Standardized Mortality Ratio for the 44 surgically treated patients surviving 6 months was 1.3. Those neurologically normal or with only mild impairment at 6 months had no identified increase in mortality. Excess mortality that was limited to individuals with severe neurologic deficit at 6 months could be identified through the first 10 years after onset. Two 6-month survivors experienced recurrent SAH.

CONCLUSIONS

Early mortality is high (47%) in patients with RCA. In patients operated on for RCA and surviving 6 months, recurrent SAH occurred in 5%. Survivorship among patients surgically treated and neurologically normal or with mild residual neurologic impairment at 6 months following presentation was similar to that expected in the general population. Survivorship among patients surgically treated who had severe residual neurologic impairment at 6 months was significantly reduced.

[Surgery of lumbar disk prolapse in Scandinavia. A questionnaire study in Scandinavian neurosurgical departments in 1993]

This article consists in a review of treatment for lumbar disc prolapse in 1993, as reported by all 22 neurosurgery units in the Nordic countries, serving a total population of 23.5 million. Of surgical operations for the condition, 37 per cent were performed by neurosurgeons-using standard lumbar discectomy in 61.3 per cent of cases, microsurgical techniques in 36 per cent of cases, and percutaneous lumbar discectomy in the remaining 2.7 per cent. Chemonucleolysis is no longer considered a viable therapeutic alternative. In the Nordic countries as a whole, the annual incidence of lumbar disc prolapse surgery is 52.5 per 100,000, though the figure varies from one country to another.

Escherichia coli DNA polymerase II catalyzes chromosomal and episomal DNA synthesis in vivo

We have investigated a role for Escherichia coli DNA polymerase II (Pol II) in copying chromosomal and episomal DNA in dividing cells in vivo. Forward mutation frequencies and rates were measured at two chromosomal loci, rpoB and gyrA, and base substitution and frameshift mutation frequencies were measured on an F'(lacZ) episome. To amplify any differences in polymerase error rates, methyl-directed mismatch repair was inactivated. When wild-type Pol II (polB+) was replaced on the chromosome by a proofreading-defective Pol II exo- (polBex1), there was a significant increase in mutation frequencies to rifampicin resistance (RifR) (rpoB) and nalidixic acid resistance (NalR) (gyrA). This increased mutagenesis occurred in the presence of an antimutator allele of E. coli DNA polymerase III (Pol III) (dnaE915), but not in the presence of wild-type Pol III (dnaE+), suggesting that Pol II can compete effectively with DnaE915 but not with DnaE+. Sequencing the RifR mutants revealed a G --> A hot spot highly specific to Pol II exo-. Pol II exo- caused a significant increase in the frequency of base substitution and frameshift mutations on F' episomes, even in dnaE+ cells, suggesting that Pol II is able to compete with Pol III for DNA synthesis on F episomes.

Whooping cough and Parkinson's disease. The Europarkinson Preparatory Activity Research Group

BACKGROUND

We reported high levodopa use and prevalences of Parkinson's Disease (PD) in periodically, time-clustered, icelandic cohorts born after major whooping cough epidemics (MWCE).

METHODS

In order to quantify a possible relationship between age at first post-birth MWCE and risk of PD we: 1) calculated cumulative incidences of PD during the period 1954-1963 in one-year Icelandic cohorts born between 1869 and 1927, using raw material from a reported survey; 2) identified MWCE from 1869 onwards in Iceland; 3) estimated cohort ages at onset of incidence period and at first MWCE; and 4) combined the above-mentioned information using log-linear models. In addition, we studied the prevalence of levodopa users in Icelandic birth cohorts during a recent period.

RESULTS

The curves of the above-mentioned incidences and prevalences in one-year birth-cohorts showed: 1) a similar, age-related, inverted V profile; and 2) a systematic notchy pattern, with peak values for one or both measurements for cohorts born during or after each of nine MWCE identified during the period 1869-1927. When 13 cohorts born in years with MWCE were excluded from the analysis, the risk of PD rose with age at first defined MWCE, with the linear increase being 8.4% per year (95% CI: -0.1-18.3%).

CONCLUSIONS

These results are consistent with reported effects of age at exposure in animal models of toxic parkinsonism, age-related changes in the dopamine receptor-GPT-binding protein-adenylatecyclase system observed in rats treated with pertussis toxin, and some PD epidemiological features. They suggest that pertussis neurotoxicity could be casually treated to PD worldwide.

Incidence of epilepsy in rural Iceland: a population-based study

PURPOSE

We wished to determine the incidence of epilepsy in the population of rural Iceland.

METHODS

Cases were identified through review of records of primary care facilities for the study population, supplemented by review of referrals to EEG facilities and neurologic specialists.

RESULTS

The incidence of epilepsy (recurrent unprovoked seizures) was 47 in 100,000. Age-specific incidence was bimodal, highest in the youngest and oldest age groups. About one third of the patients had an identifiable etiology, and one third had partial seizures. Integration of imaging and neurophysiologic data did little to modify the distribution of etiology or seizure type.

CONCLUSIONS

The present study confirms findings of other recent studies of incidence in Western Countries.

Progressive dementia and leucoencephalopathy as the initial presentation of late onset hereditary cystatin-C amyloidosis. Clinicopathological presentation of two cases

Hereditary Cystatin-C Amyloidosis (HCCA) is a genetic disorder in Icelandic families in which a defective cystatin-C amyloid protein is deposited in the walls of small and middle sized arteries. Cerebral vessels are most affected, resulting in recurrent cerebral hemorrhages and infarctions, usually with onset of clinical symptoms in the twenties or thirties and a rapidly deteriorating clinical course. The disease can be diagnosed by a skin biopsy in symptomatic patients. We report two patients (father and daughter) who did not have a known family history of the disorder and presented late in life with a progressive dementia, associated with cerebral hemorrhages in the younger patient. Cerebral MRI and CT scans of this patient showed extensive leukoencephalopathic changes. Brain tissue samples from both patients showed immunohistochemical reaction to cystatin-C in small and medium-sized cerebral arteries and extensive cortical and white matter microinfarctions. The amyloid changes were less severe in the older patient and a colocation of beta-amyloid protein and cystatin-C was observed in addition to neurofibrillary tangles and senile plaques. Subcortical and cortical infarctions were also observed. HCCA may present late in life with progressive dementia as the only clinical manifestation, reflecting a multi-infarct syndrome secondary to the amyloidosis. A coexpression of cystatin-C and beta protein may occur as in other cerebral amyloid disorders, probably as age-specific changes.

Middle lobe syndrome

Middle lobe syndrome is defined as recurrent or chronic collapse of the middle lobe of the right lung. It occurs in all age groups and is divided into an obstructive type, with a demonstrable airway occlusion, and a nonobstructive type, with a patent right middle lobe bronchus apparent on bronchoscopy. Middle lobe collapse has specific radiographic findings. Malignancy is the most common cause of the obstructive type, and infections are the second leading etiology. The nonobstructive type is associated with inflammatory conditions and bronchiectasis. In all cases, treatment is directed at the underlying cause.

[MRI of the brain as a diagnostic tool in Wilson's Disease.]

The case history of a young patient with Wilson's disease (WD) is presented. The diagnosis of WD was based on increased urinary copper excretion, the presence of Keyser-Fleisher rings, changes observed on MRI of the brain and a remote family history of WD. The patient's parents were distantly related. The MRI showed symmetrically increased signal in the basal ganglia and in the brain stem on protein density and T2 weighted images. Similar changes were later observed in the thalamic nuclei. Signal changes observed on cerebral MRI in WD and their diagnostic and prognostic significance are discussed. The importance of recognising the symptoms of WD is emphasized, as early treatment may prevent death from hepatic failure or permanent damage of the central nervous system.

Proofreading-defective DNA polymerase II increases adaptive mutation in Escherichia coli

The role of Escherichia coli DNA polymerase (Pol) II in producing or avoiding mutations was investigated by replacing the chromosomal Pol II gene (polB+) by a gene encoding an exonuclease-deficient mutant Pol II (polBex1). The polBex1 allele increased adaptive mutations on an episome in nondividing cells under lactose selection. The presence of a Pol III antimutator allele (dnaE915) reduced adaptive mutations in both polB+ cells and cells deleted for polB (polB delta 1) to below the wild-type level, suggesting that both Pol II and Pol III are synthesizing episomal DNA in nondividing cells but that in wild-type cells Pol III generates the adaptive mutations. The adaptive mutations were mainly -1 frame-shifts occurring in short homopolymeric runs and were similar in wild-type, polB delta 1, and polBex1 strains. Mutations produced by both Pol III and Pol II ex1 were corrected by the mutHLS mismatch repair system.

Wilson disease in Iceland: a clinical and genetic study

A survey of Wilson disease in Iceland has revealed two large kindreds with affected individuals. We have carried out studies of haplotypes of dinucleotide repeat polymorphisms (CA repeats) flanking the Wilson disease gene. The same mutation, a 7-bp deletion, is present in both families, and the clinical features are similar. The haplotype data and nature of the mutation support the existence of a founder chromosome carrying the mutation. This Icelandic mutation was not found in patients of Irish or Scottish origins, who could share some of the Icelandic ancestral genes. Although the protein function is predicted to be completely abolished by the deletion, predicting early-onset liver disease, we find that the patients present with later-onset neurological and psychiatric symptoms. We show that alternative splicing of the transcript in the region of the deletion could contribute to later onset, suggesting that alternative isoforms of the protein might have some functional significance.

Complications to the use of vicryl-collagen dural substitute

The authors describe 3 cases of postoperative infection as a complication after the use of vicryl-collagen dural substitute. The substitute had already partially dissolved 2 weeks after surgery with the remnant so densely adherent to the brain surface that it could not be removed without damaging the cortex. This was confirmed microscopically.

Fatty acids from cod-liver oil as skin penetration enhancers

A fatty acid extract is discharged during the refining of medicinal cod-liver oil. The fatty acid composition of the extract was determined and it was found to contain an vast variety of fatty acids. About 17% of the fatty acids consisted of saturated fatty acids, the rest was unsaturated fatty acids. The extract was an effective transdermal penetration enhancer and this effect was found to be associated with the unsaturated portion of fatty acids.

High levodopa use in periodically time-clustered, Icelandic birth cohorts. A vestige of parkinsonism etiology? Europarkinson Preparatory Activity Research Group

We evaluated levodopa use (LDU) by the Icelandic population focusing on: 1) annual gross levodopa (LD) sales from wholesalers to pharmacies for the period 1978-1990, using a reported method; 2) data from a prescription survey conducted from October 1st, 1990 to March 31st, 1991; and 3)raw and reported data on prevalences of Parkinson's disease (PD) in 1963 in this country. The standard for adjustments and reference population for LDU comparisons was the Swedish in 1984. Crude gross sales of LD in Iceland in 1990 and in Sweden in 1984 amounted to 1.67 and 1.35 DDD/1000 person days respectively. After respective adjustments for age, and for age and the infant mortality rates, taken as an indicator of health care quality, LDU in Iceland in 1990 was found to be 1.82 and 1.63 (95% CI 1.47-1.89) times that for Sweden. Prevalences of LD-prescription recipients in 1990-1991 and of PD in 1963 increased with age; however, those of drug users were higher than those of PD among the elderly. Higher-than-expected prevalences of PD and LD-prescription users (there being a partial overlap between these two categories) were found in periodically-clustered, one-year birth cohorts. These results support the notion that Iceland has a high LDU and suggest that this variation is due to a high prevalence of LD responsive disorders. Cohorts born after registered whooping cough outbreaks in Iceland may account for the magnitude and birth-related pattern of PD prevalences and LDU levels.

Involvement of Escherichia coli DNA polymerase II in response to oxidative damage and adaptive mutation

DNA polymerase II (Pol II) is regulated as part of the SOS response to DNA damage in Escherichia coli. We examined the participation of Pol II in the response to oxidative damage, adaptive mutation, and recombination. Cells lacking Pol II activity (polB delta 1 mutants) exhibited 5- to 10-fold-greater sensitivity to mode 1 killing by H2O2 compared with isogenic polB+ cells. Survival decreased by about 15-fold when polB mutants containing defective superoxide dismutase genes, sodA and sodB, were compared with polB+ sodA sodB mutants. Resistance to peroxide killing was restored following P1 transduction of polB cells to polB+ or by conjugation of polB cells with an F' plasmid carrying a copy of polB+. The rate at which Lac+ mutations arose in Lac- cells subjected to selection for lactose utilization, a phenomenon known as adaptive mutation, was increased threefold in polB backgrounds and returned to wild-type rates when polB cells were transduced to polB+. Following multiple passages of polB cells or prolonged starvation, a progressive loss of sensitivity to killing by peroxide was observed, suggesting that second-site suppressor mutations may be occurring with relatively high frequencies. The presence of suppressor mutations may account for the apparent lack of a mutant phenotype in earlier studies. A well-established polB strain, a dinA Mu d(Apr lac) fusion (GW1010), exhibited wild-type (Pol II+) sensitivity to killing by peroxide, consistent with the accumulation of second-site suppressor mutations. A high titer anti-Pol II polyclonal antibody was used to screen for the presence of Pol II in other bacteria and in the yeast Saccharomyces cerevisiae. Cross-reacting material was found in all gram-negative strains tested but was not detected in gram-positive strains or in S. cerevisiae. Induction of Pol II by nalidixic acid was observed in E. coli K-12, B, and C, in Shigella flexneri, and in Salmonella typhimurium.

On the role of monocytes/macrophages in the pathogenesis of central nervous system lesions in hereditary cystatin C amyloid angiopathy

The pathogenesis of the deposition of a variant cystatin C as amyloid in hereditary cystatin C amyloid angiopathy (HCCAA) is not known. To address this question the synthesis and secretion of cystatin C in cultured monocytes from 9 carriers of the mutated cystatin C gene (5 symptomatic and 4 asymptomatic) was examined. The quantity of cystatin C in cells and supernatants was determined by the ELISA method, Western blots were done and selected samples immunostained for cystatin C. Monocytes from individuals carrying the gene defect synthesized cystatin C that was apparently not truncated, a form found in the cerebral amyloid deposits in HCCAA, but showed a distinctly lower rate of cystatin C synthesis than monocytes from healthy controls. The main difference was that the quantity of cystatin C was significantly lower in the supernatants in monocyte cultures from carriers of the gene defect than from healthy controls, possibly due to a partial block in its secretion. This abnormal processing of the cystatin C could explain the low cerebrospinal fluid levels of cystatin C in HCCAA and might be a part of the pathogenetic pathway of amyloid deposition. Furthermore it could, through a lower extracellular concentration of this inhibitor of cysteine proteinases, contribute to destruction of the amyloidotic blood vessels, leading to the most serious clinical manifestation in HCCAA, intracerebral hemorrhage.

Piroxicam and indomethacin suppositories for painful coxarthrosis

Six orthopaedic clinics in Sweden made a comparison of the effects and side effects of Piroxicam (20 mg) and Indomethacin (100 mg) suppositories in 261 patients with painful coxarthrosis on the waiting list for total hip replacement (THR). The study was designed as a single blind study over 4 weeks. Amount of pain and range of motion was registered before the trial and compared with findings after 4 weeks, including reported side effects. Both drugs gave satisfactory pain relief without any appreciable variation on weightbearing or at rest. On the other hand, the trial showed a significant difference (p = 0.0033, Student's-test) between the two drugs as regards the frequency of side effects from the lower gastrointestinal tract, where piroxicam had a lower rate compared with indomethacin. No serious complications occurred; 16 patients dropped out, 8 in each group.

Primary cytomegalovirus infection and gastric ulcers in normal host

A 42-year-old woman presented with epigastric pain and vomiting. Upper gastrointestinal endoscopy revealed three gastric ulcers. Histologic examination of biopsies from the ulcers showed cytomegalovirus inclusion bodies. The appearance of IgM antibodies to cytomegalovirus indicated a recent and primary infection. Stored serum from her last pregnancy 17 months previously contained no cytomegalovirus antibodies. A thorough evaluation of her immune system revealed no abnormality. We are aware of only two other cases where seroconversion was documented in normal hosts. Cytomegalovirus infections in the gastrointestinal tract of normal hosts are very unusual but a common cause of morbidity in immunocompromised hosts. We believe that cytomegalovirus may have a role in the pathogenesis of gastrointestinal lesions in nonimmunocompromised patients.

Skin deposits in hereditary cystatin C amyloidosis

Clinically normal skin from 47 individuals aged 9-70 years was investigated. Cystatin C amyloid deposits were found in various locations of the skin by light and/or electron microscopy, in all 12 patients with a clinical history of hereditary cystatin C amyloidosis (HCCA). Six asymptomatic individuals, who had the Alu 1 restriction fragment length polymorphism (RFLP) marker reported to cosegregate with the disease, also had cystatin C amyloid deposits in the skin. Three asymptomatic individuals (age 17-46) belonging to the HCCA families were without amyloid in the skin but had Alu 1 RFLP marker. Skin from 12 individuals who served as controls and skin from 14 close relatives of the patients was negative for amyloid. Punch biopsy of the skin is a simple procedure which is of value for the diagnosis of HCCA, even before the appearance of clinical symptoms. This method might also be of use in following progression of the disease.

The amino terminal portion of cerebrospinal fluid cystatin C in hereditary cystatin C amyloid angiopathy is not truncated: direct sequence analysis from agarose gel electropherograms

The isolated amyloid substance in hereditary cystatin C amyloid angiopathy (HCCAA) is mainly composed of a cystatin C variant devoid of the 10 amino terminal amino acid residues of extracellular cystatin C from healthy individuals. We have developed a procedure for protein sequencing directly from agarose gel electropherograms and used this in conjunction with isoelectric focusing to investigate the amino terminal sequence of cerebrospinal fluid (CSF) cystatin C in HCCAA patients. The amino-terminal sequence determined for cystatin C from a HCCAA patient CSF sample, Xaa-Ser-Pro-Gly-Lys-Pro-Pro-Xaa-Leu-Val-Gly-Gly-Pro-Met-Xaa-Ala-Xaa-Val, showed that the protein was not amino-terminally truncated. CSF cystatin C from all nine HCCAA patients investigated was found to have an isoelectric point identical to that of native cystatin C, and the truncated form of cystatin C isolated from amyloid deposits was shown to contribute to less than 1% of the total amount of cystatin C in CSF. The total cysteine proteinase inhibitory capacity of CSF from HCCAA patients was lower than that of CSF from other patients. This decreased CSF inhibitory capacity in HCCAA patients was caused by decreased levels of cystatin C, since the levels of the other two cysteine proteinase inhibitors found in CSF, alpha 2-macroglobulin and kininogen, were significantly higher than in CSF from non-HCCAA patients.