Early noncognitive change in Alzheimer's disease and healthy aging

Recent studies in Alzheimer's disease have focused on behavioral disturbances in the more advanced stages of the illness rather than behavioral and personality changes occurring early in the disease course. We present a new instrument, the Oregon Noncognitive Inventory for Dementia (ONID), that was developed specifically for patients in the early stages of dementia, to identify subtle behavioral alterations that may precede the more severe cognitive changes of Alzheimer's disease. Mildly demented Alzheimer's patients were compared with age-matched healthy subjects on the ONID. Caregivers of these patients reported significantly more of the behaviors addressed by the ONID than did relatives of the healthy elderly. The results indicate that changes in behavior and personality can be reliably reported by family caregivers of patients with mild dementia. Future clinical applications of the ONID might include measuring change in drug trials, longitudinal studies of the progression of change, and differentiating Alzheimer's disease from other dementias based on a characteristics pattern of change.

Spirituality among caregivers

The spiritual perspectives of 17 caregiver wives of dementia victims and 23 noncaregiving wives of healthy adults were compared in a pilot study using a convenience sample. Caregiver wives used symbols such as God, and spiritual behaviors such as prayer and forgiveness as coping mechanisms. Caregivers tended to share the problems and joys of living according to their spiritual belief more often than the noncaregiver wives of healthy adults. Caregivers also engaged in private prayer and sought spiritual guidance in making decisions in their everyday life more often. The findings suggest that nursing interventions with churches as a natural network for caregivers may be useful. Prayer, forgiveness, and spiritual reading materials are resources that may be helpful to some caregivers.

Discrimination between thymic epithelial cells and peripheral antigen-presenting cells in the induction of immature T cell differentiation

During their intrathymic migration, immature CD4+ CD8+ thymocytes that express a TCR able to recognize the expressed MHC molecules are positively selected, i.e., complete their differentiation program and become mature T cells. Using the immature CD4+CD8+ T cell line DPK, which can be induced to differentiate in culture, we show here that a subset of isolated thymic epithelial cells, but not peripheral antigen-presenting cells, can induce differentiation, suggesting a unique function of these cells in T cell development. In addition, analysis of activation markers induced by thymic epithelial cells versus specific antigen gives the first direct evidence that positive selection is associated with low level cell activation. In contrast with strict affinity-avidity models of thymic selection, we propose that a specialized antigen-presenting cell environment is an essential contributor to TCR-mediated differentiation in the thymus.

Age-related differences in visual search task performance: relative stability of parallel but not serial search

The hypothesis that visual search tasks requiring effortful, serial processing are more sensitive to aging than those requiring relatively automatic, parallel processing was tested in 96 healthy adults who performed parallel and serial visual search tasks with fixed presentation times. Reaction times and error rates increased with age in both tasks, but there was no difference between young and old in the effect of increasing numbers of distractors on reaction times. However, the older subjects made significantly more errors with increasing numbers of distractors in the serial search task. Older subjects have disproportionately more difficulty performing serial compared to parallel visual search tasks than do younger subjects. Additionally, this difference is not caused solely by cautious response strategies in the elders.

Cancer associated human papillomaviruses: perinatal transmission and persistence

OBJECTIVE

To demonstrate the perinatal transmission and persistence of the cancer associated human papillomavirus types 16, 18, 31 and 33.

DESIGN

Cervical swabs were taken from pregnant women between 20 and 38 weeks of gestation. Buccal and genital swabs were taken from infants at 24 h and at six weeks after delivery and examined for HPV-16, -18, -31 and -33 DNA by the polymerase chain reaction.

SETTING

Maternity Unit at St Thomas's Hospital, London.

SUBJECTS

Thirty-one pregnant women, 16 with a previous history of cervical intraepithelial neoplasia or genital warts, or both, and their 32 infants (one set of twins).

RESULTS

Twenty of the 31 (65%) women were positive for HPV-DNA prior to delivery. Twelve of 32 (38%) and eight of 31 (26%) infants were HPV-DNA positive at 24 h and six weeks respectively. Swabs taken at 24 h demonstrated HPV type 16 in five mother-infant pairs and HPV type 18 in two mother-infant pairs. Dual infections with HPV types 16 and 18 were demonstrated in swabs from three mother-infant pairs. At six weeks, HPV-16 was demonstrated in swabs from six infants and HPV-18 in swabs from two infants.

CONCLUSIONS

Perinatal transmission of human papillomavirus types 16 and 18 occurred in 55% cases. Persistent human papillomavirus infection was demonstrated at six weeks of age. Whether acquisition of human papillomavirus during the perinatal period predisposes to an increased risk of cervical intraepithelial neoplasia among female infants in later life remains to be established. Information on the persistence of perinatally acquired human papillomavirus is required before rational vaccination programmes can be considered.

Attention deficit in Alzheimer's disease is not simulated by an anticholinergic/antihistaminergic drug and is distinct from deficits in healthy aging

OBJECTIVE

To evaluate attention deficit in Alzheimer's disease (AD) and its relationship to attention deficits associated with aging and with medications altering alertness.

METHODS

Ten patients with probable AD, 10 healthy old controls, and 15 young controls performed a covert orienting of spatial attention task. Young controls performed the task an additional time after ingestion of diphenhydramine 1 mg/kg. Reaction times were obtained following valid, neutral, and invalid cues.

RESULTS

In all groups, the reaction times were shortest for the validly cued stimuli and longest for the invalidly cued stimuli. Additionally, the AD patients performed disproportionately worse following the invalid cue than did the control groups. Young controls given diphenhydramine had decreased subjective alertness, performed worse than they did before drug but better than the old controls or AD patients, and had no disproportionate impairment with the invalid cue.

CONCLUSIONS

AD patients have disproportionate problems shifting spatial attention compared with age-matched controls. Impaired attentional performance in AD cannot be simulated in young subjects by ingestion of a combined antihistamine/anticholinergic agent at a dose sufficient to produce significant changes in alertness.

Evidence for familial factors that protect against dementia and outweigh the effect of increasing age

A positive family history is associated with increased risk for dementia. It is not known whether a negative family history with long-lived relatives predicts a reduced risk for dementia. We studied the survival rate and the occurrence of dementia in 232 parents and siblings of 43 optimally healthy individuals > or = 84 years of age and compared them with 233 parents and siblings of 51 random controls and 499 parents and siblings of 88 Alzheimer disease (AD) patients. Prevalence of dementia after age 60 years was .031 for the relatives of healthy elderly, .066 for the relatives of random controls, and .217 for the relatives of AD patients. The cumulative incidence of dementia by age 85 years was estimated as .041 (+/- .019) for the relatives of healthy elderly individuals, .102 (+/- .038) for the relatives of random controls, and .360 (+/- .037) for the relatives of AD patients. Hazard-ratio estimates suggest that the risk of dementia for the relatives of healthy elderly is 3 times lower than the risk for the relatives of random controls (P < .03) and is 11 times lower than the risk for the relatives of AD patients (P < .00005). An analysis of age at death indicated that the relatives of healthy elderly and the relatives of AD patients had a longer life span than did the relatives of random controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Variant angina in an adolescent

We describe a case of variant angina associated with acute myocardial ischemia in an adolescent presenting with severe chest pain and transient ST elevation. Subsequent cardiac catheterization revealed normal coronary anatomy, and the patient has been asymptomatic since discharge on calcium channel blockers. Variant angina is a rare cause of chest pain in adolescents.

Changes in students' attitudes following a course on death and dying: a controlled comparison

This study evaluated the effect of a death-education course on the death-related anxiety and attitudes toward death of 71 medical students not yet exposed to clinical rotations and four health care professionals. The Collect-Lester Fear of Death Scale and a semantic differential technique measuring attitudes toward the dying patient and his or her family were administered to course attendees before and after the course and to freshman students not taking the course. The 75 course attendees and the 93 controls completed the baseline measures, and 71 course attendees and 46 controls responded to the post-course evaluation. The course did not produce significant changes on the four Collett-Lester subscales, although there was an overall decline in anxiety when the two groups were combined (p = 0.035). Semantic differential scales showed no change for controls but a marked improvement in attitudes toward "treating the dying patient" and "dealing with the dying patient's family" for attendees (p < 0.001 for both). In summary, course participation resulted in improvement in students' attitudes toward dealing with death.

Neurologic function in the optimally healthy oldest old. Neuropsychological evaluation

We examined cognition on a wide range of standardized neuropsychological tests in two groups of optimally healthy, elderly volunteers. One was composed of community-dwelling, functionally independent individuals aged 84 years and older, and the other group was nearly 20 years younger. The effect of aging was greatest on visual perceptual and constructional tasks rather than on memory tasks. Many cognitive functions were relatively well preserved in the optimally healthy oldest old.

Reductions in parietal and temporal cerebral metabolic rates for glucose are not specific for Alzheimer's disease

Reduction in the regional cerebral metabolic rate for glucose (rCMRglc) in the parietal and temporal regions has been shown in Alzheimer's disease (AD). The specificity of these findings for this disease state is uncertain. We repeatedly measured rCMRglc with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in the resting state in a 68 year old man with slowly progressive dementia who, during life, was initially diagnosed as having dementia of the Alzheimer type, then Parkinson disease with dementia, but was found to have only Parkinson's disease at necropsy. Metabolic ratios (rCMRglc/mean grey CMRglc) were significantly (p < 0.05) reduced in parietal and temporal regions, as well as in the prefrontal and premotor areas. This pattern was similar in regional distribution and magnitude of the defect to that seen in patients with probable AD. These results suggest that reductions of glucose metabolism in association neocortex in AD are not specific to the disease process, but may be related to the dementia state.

Interuncal distance: marker of aging and Alzheimer disease

PURPOSE

To evaluate the utility of a recently reported simple measure of brain atrophy on MR imaging, the interuncal distance (IUD).

METHODS

Measurements of the IUD were made over a 12-month interval in 10 patients with probable early Alzheimer disease and in a comparison group of age-matched healthy control subjects. The measurements were made in both the transaxial and coronal planes.

RESULTS

Significant group differences for the coronal measurement of IUD were found in both the absolute value of the measurement and the IUD corrected for head size. There was overlap in IUD between the disease and the control groups. These differences were not found for the transaxial IUD. Significant positive correlations of the IUD with Mini-Mental State Examination score and Clinical Dementia Rating Scale stage were observed. Over the age range tested, age was not significantly correlated with IUD in the sample.

CONCLUSIONS

The interuncal distance (IUD) is not a useful screening measurement for Alzheimer disease.

The UL16 gene of human cytomegalovirus encodes a glycoprotein that is dispensable for growth in vitro

The UL16 gene of human cytomegalovirus (HCMV) encodes a predicted translation product with features characteristic of glycoproteins (signal and anchor sequences and eight potential N-linked glycosylation sites). Antisera were raised against the UL16 gene product expressed in Escherichia coli as a beta-galactosidase fusion protein. The antisera detected a 50-kDa glycoprotein in HCMV-infected cells that was absent from purified virions. The UL16 glycoprotein was synthesized at early times after infection and accumulated to the highest levels at late times after infection. A recombinant HCMV in which UL16 coding sequences were interrupted by a lacZ expression cassette was constructed by insertional mutagenesis. Analysis of the phenotype of the recombinant virus indicated that the UL16 gene product is nonessential for virus infectivity and growth in tissue culture.

Differentiation of an immature T cell line: a model of thymic positive selection

Thymocyte differentiation is dependent upon recognition of major histocompatibility complex (MHC) molecules on thymic stroma, a process called positive selection. Here we describe an immature CD4+8+ T cell line derived from a TCR transgenic mouse that differentiates into CD4+8- cells in response to antigen and nonthymic antigen-presenting cells. When injected intrathymically, these cells differentiate in the absence of antigen. The ability of immature T cells to recognize MHC molecules in the absence of foreign antigen in the thymus can thus be attributed to a unique property of thymic antigen-presenting cells. These studies also demonstrate the phenotypic and functional changes associated with TCR-mediated T cell maturation and establish an in vitro model system of positive selection.

Screening program for colorectal cancer: effect on stage distribution

BACKGROUND

The prognosis of patients with colorectal cancer is related to stages of disease at the time of diagnosis. Ultimately, the goal of fecal occult blood test (FOBT) screening programs is to reduce colorectal cancer mortality.

METHODS

We reviewed the medical records and pathology reports of all 60 Harvard Community Health Plan (HCHP) members who were diagnosed as having colorectal cancer during the 2 years after our FOBT screening program began. The stage distribution of these 60 cases were compared with that of 76 cases diagnosed at HCHP before the FOBT screening program was started.

RESULTS

Eight of 60 colorectal cancers diagnosed after the FOBT screening program was begun (13%) were diagnosed as a result of a positive screening test (Group I). The remaining 52 cases (87%) were diagnosed as a result of symptoms, physical findings, and/or the presence of anemia (Group II). Three of 8 Group I colorectal cancers (38%) were stage A, as compared with 8 of 52 of Group II colorectal cancers (15%). None of the 8 Group I colorectal cancers was stage D (metastatic) at the time of diagnosis, as compared with 11 of 52 Group II colorectal cancers (21%).

CONCLUSIONS

We observed a favorable shift in the stage distribution of colorectal cancers diagnosed at HCHP after the FOBT screening program began (p less than .05). The shift was not attributable only to FOBT screening. We believe that the educational components of the program were important to its effectiveness. Our results support continued use of FOBT at HCHP.

Involvement of the same region of the T cell antigen receptor in thymic selection and foreign peptide recognition

The Ag receptor (TCR) on T lymphocytes has been shown to be specific for foreign antigenic peptides bound to MHC-encoded molecules. During T cell differentiation in the thymus this same TCR mediates the recognition of MHC molecules in the absence of foreign Ag, a process termed positive selection. To analyze the structural relationship between MHC-restricted Ag recognition and positive selection, we characterized two different transgenic lines of mice bearing TCR specific for pigeon cytochrome c and the Ek class II MHC molecule. The two TCR expressed in these animals differed by only one amino acid in the V-J junction of the alpha-chain. In vitro, we find that this TCR difference alters Ag fine specificity. Analysis of transgenic animals demonstrates that this change in the putative third complementarity determining region of the TCR also alters the specificity of positive selection in the thymus. These results suggest that the diversity of a TCR region that can be shown to affect the specificity of foreign Ag recognition may be influenced by selection in the thymus. The findings presented here are discussed in relation to the possible role of self-peptides in positive selection.

Involvement of the same region of the T cell antigen receptor in thymic selection and foreign peptide recognition

The Ag receptor (TCR) on T lymphocytes has been shown to be specific for foreign antigenic peptides bound to MHC-encoded molecules. During T cell differentiation in the thymus this same TCR mediates the recognition of MHC molecules in the absence of foreign Ag, a process termed positive selection. To analyze the structural relationship between MHC-restricted Ag recognition and positive selection, we characterized two different transgenic lines of mice bearing TCR specific for pigeon cytochrome c and the Ek class II MHC molecule. The two TCR expressed in these animals differed by only one amino acid in the V-J junction of the alpha-chain. In vitro, we find that this TCR difference alters Ag fine specificity. Analysis of transgenic animals demonstrates that this change in the putative third complementarity determining region of the TCR also alters the specificity of positive selection in the thymus. These results suggest that the diversity of a TCR region that can be shown to affect the specificity of foreign Ag recognition may be influenced by selection in the thymus. The findings presented here are discussed in relation to the possible role of self-peptides in positive selection.

In vivo and in vitro clonal deletion of double-positive thymocytes

To study the processes of thymic development, we have established transgenic mice expressing and alpha/beta T cell antigen receptor (TCR) specific for cytochrome c associated with class II major histocompatibility complex (MHC) molecules. The transgenic TCR chains are expressed by most of the thymocytes in these mice, and these cells have been shown to efficiently mature in association with Ek- and Ab-encoded class II MHC molecules. This report describes a characterization of the negative selection of these transgenic thymocytes in vivo that is associated with the expression of As molecules. Negative selection by As molecules appears to result in the deletion of a late stage of CD4/CD8 double-positive thymocytes in that there is a virtual absence of transgenic TCR bearing CD4 single-positive thymocytes. This phenotype is accompanied by the appearance of CD4/CD8 double-negative thymocytes and peripheral T cells that are functionally antigen reactive. The process of negative selection has also been investigated using an in vitro culture system. Upon presentation of cytochrome c by Eb-expressing nonthymic antigen-presenting cells, there occurs an antigen dose-dependent deletion of the majority of CD4/CD8 double-positive thymocytes. In contrast, presentation of Staphylococcal enterotoxin A by Eb in vitro results in minimal deletion of double-positive thymocytes. In addition, we use this in vitro model to examine the effects of cyclosporin A on negative selection. In contrast to its effects on mature T cells, and the findings of others in vivo, cyclosporin A does not inhibit antigen-induced deletion of double-positive thymocytes. Finally, a comparison of the antigen dose responses for thymocyte deletion and for peripheral T cell activation indicates that double-positive thymocyte recognition is more sensitive than mature T cells to antigen recognition.

Osteopathy: the 'orthodox' alternative

Janice Kaye believes that osteopathy can significantly reduce employee absenteeism. Here she explains its unique system of treatment and argues for its use in OH departments.

Electrophysiologic function in the healthy, extremely old

We analyzed conventional EEG, computerized EEG frequency analysis (CEEGFA), and long-latency auditory evoked potentials in 22 extremely healthy subjects over age 84 (range, 84 to 98) and compared them with 11 younger elderly subjects as well as subjects under age 65 years. Intermittent temporal slowing in the conventional EEG was present in 50% of the elderly. Its presence was related to the presence of white matter hyperintensities on MRI but not to blood pressure or cognitive function. The posterior peak frequency determined by CEEGFA was maintained above 8 Hz in all subjects under age 84, but was between 7 and 8 Hz in five of 22 subjects over age 84 years. Three other CEEGFA variables studied (relative theta, relative alpha, and median-power frequency in the posterior channels) all demonstrated a significant change with age, most marked above age 80 years. Well-defined P3s were not present in five of 22 subjects over age 84 and in only one of 38 subjects under age 84 years. The P3 latency increased by 0.8 msec per year throughout the adult age range, while the P3 amplitude was relatively stable until the eighties. This study highlights the effects of healthy aging on clinical electrophysiologic tests of cerebral function.

The significance of age-related enlargement of the cerebral ventricles in healthy men and women measured by quantitative computed X-ray tomography

OBJECTIVE

(1) To establish the range of cerebral atrophy across the adult age spectrum in optimally healthy, rigorously evaluated individuals. (2) To determine, across the age spectrum, the relation of gender and cerebral atrophy (as measured by ventricular enlargement) to cognitive function.

DESIGN

Cross-sectional comparison by age and gender.

SETTING

Ambulatory research unit.

PARTICIPANTS

Sixty-four healthy men (mean age +/- SD = 49 +/- 18 yr) and 43 healthy women (51 +/- 18 yr) volunteers enrolled in a longitudinal study of healthy aging. The population was selected for optimal health; all were rigorously screened to exclude medical and psychiatric illness.

MAIN OUTCOME MEASURES

Brain atrophy by CT scan and cognitive function by standardized neuropsychological testing.

RESULTS

After correction for inter-subject variability in cranial volume, women had smaller lateral, but not third, ventricles. For both genders, there were significant differences with age in ventricular volume. After an approximately constant 20% increase in ventricular volume per decade in both genders, a precipitous increase in volume was found beginning in the fifth decade in men and in the sixth decade in women. In men and women, there was a significant negative correlation between ventricular volume and the sum of performance scale scores on the Wechsler Adult Intelligence Scale (WPSS) but not in the sum of the verbal scale scores (WVSS). However, after controlling for age, ventricular volume no longer significantly contributed to the relation between age and WPSS.

CONCLUSIONS

In unequivocally healthy individuals, gender plays an important role in age-associated central cerebral atrophy as measured by progressive ventricular enlargement. Increase in ventricle volume independent of age, does not explain normal age-related declines seen in WPSS scores.

Construction and properties of a mutant of herpes simplex virus type 1 with glycoprotein H coding sequences deleted

A mutant of herpes simplex virus type 1 (HSV-1) in which glycoprotein H (gH) coding sequences were deleted and replaced by the Escherichia coli lacZ gene under the control of the human cytomegalovirus IE-1 gene promoter was constructed. The mutant was propagated in Vero cells which contained multiple copies of the HSV-1 gH gene under the control of the HSV-1 gD promoter and which therefore provide gH in trans following HSV-1 infection. Phenotypically gH-negative virions were obtained by a single growth cycle in Vero cells. These virions were noninfectious, as judged by plaque assay and by expression of beta-galactosidase following high-multiplicity infection, but partial recovery of infectivity was achieved by using the fusogenic agent polyethylene glycol. Adsorption of gH-negative virions to cells blocked the adsorption of superinfecting wild-type virus, a result in contrast to that obtained with gD-negative virions (D. C. Johnson and M. W. Ligas, J. Virol. 62:4605-4612, 1988). The simplest conclusion is that gH is required for membrane fusion but not for receptor binding, a conclusion consistent with the conservation of gH in all herpesviruses.

HLA-A2, or a closely linked gene, confers susceptibility to early-onset sporadic Alzheimer's disease in men

There is a weak association between Alzheimer's disease (AD) and the histocompatibility antigen HLA-A2, suggesting that A2 has either a minor role in AD or a major role in a subtype of it. To test these alternatives, we studied 54 consecutively ascertained AD patients diagnosed by NINCDS-ADRDA criteria. Patients had a higher frequency of A2 than control subjects, primarily due to the elevated frequency of this antigen in men with early onset of dementia (less than or equal to 60 years): 92% of early-onset men had A2 as compared with 44% of controls. This finding suggests that A2, or a closely linked gene, confers susceptibility to early-onset AD in men. Furthermore, A2 appears to be primarily associated with sporadic AD, rather than with the familial subtype.

Screening program for colorectal cancer: participation and follow up

The benefit of screening for colorectal cancer with the fecal occult blood test (FOBT) remains controversial. In 1985, an annual FOBT screening program for colorectal cancer was begun at Harvard Community Health Plan (HCHP). We subsequently reviewed 409 randomly selected medical records of members over age 50 to determine whether screening had been performed, how members with positive test results were evaluated by their physicians, and what gastrointestinal lesions were found as a result of positive screening tests. One hundred and ninety seven of 409 members (48%) were screened at least once during the two-year study period. One hundred and eight of 180 members (60%) who had one periodic health review (PHR) and 72 of 88 members (82%) who had two or more PHRs during the study period were screened at least once. Sixteen of 197 members who were screened at least once (8%) had positive tests. Eleven of the 16 members with positive tests were adequately evaluated by their physicians. Four had colorectal polyps and five had some other benign gastrointestinal lesion. The conclusion drawn is that FOBT screening for colorectal cancer is practical in the HMO setting. Members who have periodic health reviews are more likely to participate in screening. Physicians and members must be better educated to ensure adequate evaluation of positive tests.

Structure and specificity of the T cell antigen receptor

The antigen receptor on T lymphocytes is a multi-chain complex of which two chains determine its specificity for antigen. Although these receptor chains possess genetic and structural similarities with membrane-bound immunoglobulin, the B cell antigen receptor, they endow T cells with a distinct specificity. Unlike B cells, T cells recognize foreign antigenic properties only in the form of proteolytic fragments bound to molecules encoded by the major histocompatibility complex. In addition, one stage of the development of T cells in the thymus is dependent upon an antigen receptor-mediated event. Utilizing the response to a well defined antigen as a model system, we discuss the relationship between receptor structure and the specificity of these recognition events.

Comparison of rapid immunofluorescence assay to cell culture isolation for the detection of influenza A and B viruses in nasopharyngeal secretions from infants and children

In the hospital setting it is often critical to isolate patients appropriately in order to prevent nosocomial infection. This is especially true with respiratory infection in infants and young children. At the present time a rapid immunofluorescence assay (IFA) for respiratory syncytial and parainfluenza viruses is routinely carried out in our laboratory. During January and February of 1990 we used monoclonal antibodies specific for influenza A and B viruses (Baxter-Bartels, Bellevue, WA) in this rapid IFA. 152 samples of NPS were tested by cell culture isolation (CCI) and IFA for the presence of influenza antigens. Twenty-seven samples were positive by both methods, and 114 were negative by both. Three samples were positive by IFA and negative by CCI, while eight samples were positive by CCI and negative by IFA. Five of these eight samples were not positive until 10 to 14 days after inoculation into cell culture, suggesting that the virus inoculum was small. Using CCI as the 'gold' standard, IFA was 90% sensitive and 93% specific. Because of its turn-around time (2-4 h) and acceptable sensitivity and specificity, IFA for influenza viruses will be a routine test in our diagnostic laboratory during the influenza season.

Plasticity in the aging brain. Reversibility of anatomic, metabolic, and cognitive deficits in normal-pressure hydrocephalus following shunt surgery

The course of idiopathic normal-pressure hydrocephalus was studied in a 78-year-old woman with a 4-year history of progressive dementia who underwent neuropsychologic testing, quantitative x-ray computed tomography, magnetic resonance imaging, and positron emission tomography with fludeoxyglucose F 18 to measure rates of regional cerebral glucose utilization. Preshunt cognitive testing demonstrated progressive deterioration during 2 years, and positron emission tomography showed significant reductions in regional cerebral glucose utilization of 34% to 49% as compared with age- and sex-matched control subjects in frontal, temporal, parietal, and whole brain regions. Periodic testing, carried out during a 2-year period after shunt surgery, showed steady improvement in clinical status. Parallel to the clinical changes, there was a significant reversal in neuropsychologic test scores with increased brain volume and increased regional cerebral glucose utilization in several brain regions. These results documented the considerable potential for recovery of compromised brain function in older subjects even after 4 years of progressive brain disease.

A T cell receptor V alpha region selectively expressed in CD4+ cells

The peripheral TCR V beta repertoire is strongly influenced by the processes of negative selection (deletion) and positive selection in the thymus. In order to investigate whether such selection events influence the V alpha repertoire, we have produced an anti-V alpha 11 mAb. This antibody was made by immunization with a chimeric TCR:Ig protein containing V alpha 11 in place of the VH of an IgG2a, lambda Ig. This scheme optimizes the specificity of immunization and facilitates the screening procedure. The antibody recognizes a panel of V alpha 11-expressing T cell clones. Analysis of mouse strains indicates that the antibody recognizes V alpha 11 only in mice of the C57 background. The expression of the epitope on peripheral T cells is strongly biased to the CD4+ subset, suggesting positive selection of V alpha 11 on class II MHC molecules. In some strain comparisons, the percentage of V alpha 11-expressing T cells in the CD4+ subset was elevated in I-E+ relative to I-E- strains. These data suggest that V alpha 11 can differentially influence the selection of T cells into the CD4+/CD8+ subsets.

A T cell receptor V alpha region selectively expressed in CD4+ cells

The peripheral TCR V beta repertoire is strongly influenced by the processes of negative selection (deletion) and positive selection in the thymus. In order to investigate whether such selection events influence the V alpha repertoire, we have produced an anti-V alpha 11 mAb. This antibody was made by immunization with a chimeric TCR:Ig protein containing V alpha 11 in place of the VH of an IgG2a, lambda Ig. This scheme optimizes the specificity of immunization and facilitates the screening procedure. The antibody recognizes a panel of V alpha 11-expressing T cell clones. Analysis of mouse strains indicates that the antibody recognizes V alpha 11 only in mice of the C57 background. The expression of the epitope on peripheral T cells is strongly biased to the CD4+ subset, suggesting positive selection of V alpha 11 on class II MHC molecules. In some strain comparisons, the percentage of V alpha 11-expressing T cells in the CD4+ subset was elevated in I-E+ relative to I-E- strains. These data suggest that V alpha 11 can differentially influence the selection of T cells into the CD4+/CD8+ subsets.

Cerebrospinal fluid production is reduced in healthy aging

In order to study age-related differences in cerebrospinal fluid (CSF) production in humans, we measured the rate of CSF production in 7 young (age 21 to 36 years) and 7 elderly (age 67 to 84 years) healthy volunteers, using a modified Masserman method. In addition, we evaluated CSF protein gradients by collecting CSF in serial fractions up to the 30th ml and assaying for total protein concentration. The mean rate of CSF production was significantly less in the elderly than in the young subjects. Mean CSF total protein concentrations were higher in the elderly than in the young, and significant rostrocaudal protein gradients with similar slopes were present in both groups. However, there was no correlation between CSF production and CSF total protein concentrations or protein gradient slopes. Age-related reductions in CSF production, together with the ventricular dilatation that occurs with aging, should presumably result in reduced CSF turnover and therefore influence measured concentrations of lumbar CSF constituents.

Selective development of CD4+ T cells in transgenic mice expressing a class II MHC-restricted antigen receptor

T lymphocytes are predisposed to recognition of foreign protein fragments bound to cell-surface molecules encoded by the major histocompatibility complex (MHC). There is now compelling evidence that this specificity is a consequence of a selection process operating on developing T lymphocytes in the thymus. As a result of this positive selection, thymocytes that express antigen receptors with a threshold affinity for self MHC-encoded glycoproteins preferentially emigrate from the thymus and seed peripheral lymphoid organs. The specificity for both foreign antigen and MHC molecules is imparted by the alpha and beta chains of the T-cell antigen receptor (TCR). Two other T-cell surface proteins, CD4 and CD8, which bind non-polymorphic regions of class II and class I MHC molecules respectively, are also involved in these recognition events and play an integral role in thymic selection. In order to elucidate the developmental pathways of class II MHC-restricted T cells in relation to these essential accessory molecules, we have produced TCR-transgenic mice expressing a receptor specific for a fragment of pigeon cytochrome c and the Ek (class II MHC) molecule. The transgenic TCR is expressed on virtually all T cells in mice expressing Ek. The thymuses of these mice contain an abnormally high percentage of mature CD4+CD8- cells. In addition, the peripheral T-cell population is almost exclusively CD4+, demonstrating that the MHC specificity of the TCR determines the phenotype of T cells during selection in the thymus.

Serial quantitative CT analysis of brain morphometrics in adult Down's syndrome at different ages

Quantitative CT demonstrated increased CSF and 3rd ventricular volumes, and decreased gray matter and white matter volume, in older (greater than 45 years) Down's syndrome (DS) adults with dementia as compared with younger DS adults. Serial CT studies repeated after periods of up to 2 years demonstrated significant progressive cerebral atrophy. Older DS adults without dementia, but with cognitive decline, did not show cerebral atrophy as compared with young DS subjects. These results suggest brain atrophy must be present to accompany dementia in older DS subjects, despite the presence of Alzheimer's disease neuropathology in all older subjects. The Alzheimer's disease process in DS may occur in 2 stages, the 1st with neuropathology and cognitive decline, the 2nd with additional cerebral atrophy and dementia.

Nonlocal thermodynamic equilibrium effects in stratospheric HF by collisional energy transfer from electronically excited O(2) and implications for infrared remote sensing

A possible nonlocal thermodynamic equilibrium (non-LTE) effect involving stratospheric HF arising from the direct photochemical excitation of vibrationally excited HF by collisional energy transfer from electronically excited O(2) [O(2)((1)Delta), O(2)((1)Sigma)] is presented. Although this non-LTE effect is smaller than one associated with the direct solar excitation of both HF(nu= 1) and HF(nu= 2), calculations show that inclusion of the mechanism proposed here into retrieval algorithms is necessary if correct daytime upper stratosphere HF profiles are to be inferred in future infrared thermal emission measurements. Accurate determinations of the state-to-state rate constants of the reactions involved in these excitation processes and of the quenching rates of vibrationally excited HF are needed if IR thermal emission techniques are to be accurately employed in the measurement of stratospheric HF.

Expression of a hybrid immunoglobulin-T cell receptor protein in transgenic mice

We have constructed a hybrid immunoglobulin (VDJH)-T cell receptor (C alpha) gene using the VDJH exon from a digoxin-specific antibody. This gene was used to make a line of transgenic mice. The hybrid VDJH-C alpha protein is expressed on a subset of T cells in these mice, and we have shown that it forms part of a functional TCR complex by the criteria of coprecipitation and comodulation of CD3 and TCR beta chain components and T cell activation with anti-idiotypic antibodies or digoxin. Furthermore, in cells expressing the hybrid protein, there is allelic exclusion of endogenous TCR alpha genes. We discuss the implications for the comparative structure of T cell receptors and immunoglobulins.

Anthropometry for children's spectacle frames

Facial measurements of 154 Caucasian children aged 5-14 were taken, to provide statistical information for spectacle frame manufacturers. The main differences compared with adult measurements were in the following dimensions: temple width, head width, bridge height, projection, splay angle and front to bend. The range of the 'distance between rims' measurement of adults, was similar to that of children. A number of differences between this group and a small group of Afro-Caribbean children was encountered.

Radiological loosening after cemented hip replacement for juvenile chronic arthritis

We reviewed the results of 14 total hip replacements in patients with juvenile chronic arthritis. The mean age at operation was 16 years (range 12 to 22 years); follow-up was from four to 11 years (mean 8.5 years). Postoperatively pain relief was sustained in all but one hip, while movement generally remained significantly restricted. No hip has as yet required a revision operation, although eight hips (57%) show radiological changes suggestive of impending failure. All patients had severe polyarticular involvement with associated restriction of locomotor activity. Potential causes contributing to loosening such as continuing diaphyseal bone growth and increased immunocompetence in adolescence are discussed.

Analysis of specificity for antigen, Mls, and allogenic MHC by transfer of T-cell receptor alpha- and beta-chain genes

The majority of peripheral T lymphocytes bear cell-surface antigen receptors comprised of a disulphide-linked alpha beta dimer. In an immune response, this receptor endows T cells with specificities for foreign antigenic protein fragments bound to cell surface glycoproteins encoded in the major histocompatibility complex (MHC). At a high frequency (greater than 1%), the same population of T lymphocytes responds to allogeneic MHC glycoproteins, or to differences at other genetic loci termed Mls, in conjunction with MHC. The alpha beta-antigen receptor has been implicated in alloreactivity and Mls reactivity. In fact, many monoclonal T-cell lines recognize a foreign protein fragment bound to self-MHC molecules and, in addition, recognize allogeneic MHC glycoproteins, an Mls-encoded determinant, or both. For at least one T-cell clone, a monoclonal antibody directed against the alpha beta antigen receptor has been shown to block activation induced by either antigen-bound self-MHC or by allogeneic MHC. However, it remains to be demonstrated directly that a single alpha beta receptor can mediate antigen specificity, alloreactivity and Mls reactivity, a prerequisite to understanding the structural basis of these high-frequency cross-reactivities. To address this issue we have performed transfers of receptor chain genes from a multiple-reactive T-cell clone into an unrelated host T lymphocyte. We now demonstrate definitively that the genes encoding a single alpha beta-receptor chain pair can transfer the recognition of self-MHC molecules complexed with fragments of antigen, allogeneic MHC molecules, and an Mls-encoded determinant (presumably in conjunction with MHC). In this case the transfer of antigen specificity and alloreactivity requires a specific alpha beta-receptor chain combination, whereas Mls reactivity can be transferred with the beta-chain gene alone into a recipient expressing a randomly selected alpha-chain.

Alpha-melanocyte-stimulating hormonelike immunoreactivity is increased in cerebrospinal fluid of patients with Parkinson's disease

We measured alpha-melanocyte-stimulating hormonelike immunoreactivity in cerebrospinal fluid of 12 healthy control subjects and nine patients with Parkinson's disease, four of whom had never been treated. Mean cerebrospinal fluid alpha-melanocyte-stimulating hormonelike immunoreactivity concentration was two-fold greater in parkinsonian patients (44.1 +/- 9.3 [SD] pg/mL) as compared with control subjects (21.8 +/- 10.0 pg/mL). No significant correlation was found between cerebrospinal fluid alpha-melanocyte-stimulating hormonelike immunoreactivity concentrations and patient age, disease severity, or duration of disease. These results suggest a functional relation between dopaminergic and melanotropinergic systems in the human brain.

Cerebrospinal fluid neurochemistry in the myoclonic subtype of Alzheimer's disease

Monoamine metabolites, biopterin, acetylcholinesterase (AChE) activity, and somatostatin-like immunoreactivity (SLI) were determined in the lumbar cerebrospinal fluid (CSF) of 24 patients with dementia of the Alzheimer type (DAT) without myoclonus or extrapyramidal signs, in 8 patients with DAT and myoclonus, and in 14 age-matched healthy control subjects. In patients with DAT with myoclonus as compared with both DAT patients without myoclonus and control subjects, the concentrations of homovanillic acid and biopterin were significantly decreased. 5-Hydroxyindoleacetic acid was significantly lower in patients with myoclonic DAT as compared to patients with nonmyoclonic DAT, but not significantly lower than in control subjects. CSF AChE and SLI were significantly reduced in patients with DAT with or without myoclonus, as compared with control subjects, but AChE and SLI were not significantly different between dementia groups. These results suggest that DAT patients with myoclonus represent a distinct clinical and neurochemical DAT subtype.

NIH conference. Alzheimer disease: clinical and biological heterogeneity

The clinical and biological features of Alzheimer disease are not uniform in their expression; heterogeneity is evident in the disease's clinical, anatomic, and physiologic characteristics. The presence of considerable intersubject and intrasubject heterogeneity suggests that subtypes of the disease exist. We define subtypes of Alzheimer disease in regard to the behavioral features (for example, predominant right or left hemisphere, or symmetrical impairment), inheritance (familial or sporadic), dosage of chromosome 21 (presence of the Down syndrome), time course of progression, age of onset (presenile or senile), and presence or absence of motor deficit (myoclonus or signs of an extrapyramidal syndrome). Studies of regional cerebral glucose metabolism with positron emission tomography and [18-fluorine] fluorodeoxyglucose show focal alterations in glucose use, with cerebral metabolic asymmetries in patients with Alzheimer disease that are related to the nature of the cognitive deficit. Serial roentgenographic computed tomographic studies show heterogeneous rates of lateral ventricle enlargement in the disease that are related to rates of cognitive decline. Similar anatomic and physiologic abnormalities are also found in persons 45 years of age or older who have the Down syndrome. Furthermore, patients with Alzheimer disease who have extrapyramidal dysfunction or myoclonus are a distinct subgroup, with specific abnormalities of central monoamine markers of dopamine metabolism, serotonin metabolism, and the hydroxylation cofactor, biopterin. The concept of subtypes in Alzheimer disease serves as a model with which the interactions of genetic influences with environmental factors can be examined.

CSF alpha-MSH in dementia of the Alzheimer type

We measured CSF alpha-melanocyte stimulating hormone-like immunoreactivity (alpha-MSH-LI) in 35 patients with dementia of the Alzheimer type (DAT) and in 27 healthy control subjects. Mean alpha-MSH-LI concentration was significantly decreased in DAT patients as compared with age-matched controls. However, when the DAT patients were analyzed according to age at onset of dementia or presence of extrapyramidal signs, alpha-MSH-LI concentrations remained significantly lower than in controls only in DAT patients with late onset of dementia (greater than 65 years of age). No correlation was found between alpha-MSH levels and degree of mental impairment. A significant negative correlation was found between CSF concentrations of alpha-MSH and homovanillic acid in the group of all DAT patients (p less than 0.001). These results suggest that hypothalamic neurons which produce pro-opiomelanocortin-related peptides may be involved in Alzheimer's disease.

Dementia in Down's syndrome: cerebral glucose utilization, neuropsychological assessment, and neuropathology

We measured the cerebral metabolic rate for glucose (CMRglc) with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in a 47-year-old man with trisomy 21 Down's syndrome (DS) and autopsy-confirmed Alzheimer's disease. Dementia was evident from a confirmed history of cognitive decline, memory loss, and personality change. CMRglc in the subject was compared with the mean obtained in 13 healthy younger DS subjects, aged 19 to 33 years. Test scores of general intelligence, visuospatial ability, language, and memory function showed poorer performance in the older subject compared with the younger group. Mean hemispheric CMRglc in the older DS subject was 28% less than in the young DS group, and marked hypometabolism was evident in parietal and temporal lobe association cortices. At autopsy, extensive neuropathology was noted, especially in the parietal and temporal cortical regions, more so than reported in DS subjects without documented dementia. This study is the first complete assessment of cerebral metabolism, neuropsychological competence, and neuropathology in a DS subject with a documented course of dementia, and demonstrates the superimposition of Alzheimer type dementia on previous mental retardation.

Cerebrospinal fluid monoamine markers are decreased in dementia of the Alzheimer type with extrapyramidal features

We measured monoamine metabolites and biopterin in the CSF of 37 patients with dementia of the Alzheimer type (DAT), with or without extrapyramidal signs, and in 14 age-matched healthy controls. Compared with concentrations in DAT and controls, the concentrations of homovanillic acid (HVA) and biopterin were significantly decreased in DAT with extrapyramidal signs (EDAT). CSF 3-methoxy-4-hydroxy-phenethyleneglycol and 5-hydroxyindoleacetic acid did not differ significantly among these groups. Age at onset of dementia was positively correlated with CSF HVA (r = 0.49, p less than 0.05). The two dementia groups did not differ significantly in the extent of ventricular dilation as measured by quantitative CT, but EDAT patients had lower Mini-Mental State Examination scores than did DAT patients. When patients were matched for age and dementia severity, CSF HVA and biopterin concentrations remained significantly lower in EDAT than in DAT patients. These results indicate that EDAT patients form a distinct subgroup of DAT with evidence of central monoamine dysfunction.