Prevalence and Risk Factors of Blindness Among Primary Angle Closure Glaucoma Patients in the United States: An IRIS Registry Analysis

PURPOSE

To assess the prevalence and risk factors of blindness among patients newly diagnosed with primary angle closure glaucoma (PACG) in the United States.

DESIGN

Retrospective cross-sectional study.

METHODS

Eligible patients from the American Academy of Ophthalmology (AAO) Intelligent Research in Sight (IRIS) Registry had newly diagnosed PACG, defined as: 1) observable during a 24-month lookback period from index date of PACG diagnosis; 2) no history of eye drops, laser, or cataract surgery unless preceded by a diagnosis of anatomical narrow angle (ANA); and 3) no history of glaucoma surgery. Logistic regression models were developed to identify risk factors for any (one or both eyes) or bilateral (both eyes) blindness (visual acuity ≤20/200) at first diagnosis of PACG.

RESULTS

Among 43,901 eligible patients, overall prevalence of any and bilateral blindness were 11.5% and 1.8%, respectively. Black and Hispanic patients were at higher risk of any (odds ratios [ORs] 1.42 and 1.21, respectively; P < .001) and bilateral (ORs 2.04 and 1.53, respectively; P < .001) blindness compared with non-Hispanic White patients adjusted for ocular comorbidities. Age <50 or >80 years, male sex, Medicaid or Medicare insurance product, and Southern or Western practice region also conferred a higher risk of blindness (OR > 1.28; P ≤ .01).

CONCLUSIONS

Blindness affects 1 of 9 patients with newly diagnosed PACG in the IRIS Registry. Black and Hispanic patients and Medicaid and Medicare recipients are at significantly higher risk. These findings highlight the severe ocular morbidity among patients with PACG and the need for improved disease awareness and detection methods.

Tumour size criteria for Group D and E eyes in the International Classification System for Retinoblastoma: effects on rates of globe salvage and high-risk histopathologic features

PURPOSE

To determine the significance of large tumour size as a criteria for classifying advanced intraocular retinoblastoma, analysing rates of globe survival and high-risk (HE) histopathologic features.

METHODS

Retrospective chart review of 212 eyes diagnosed with Group D (111 eyes) or Group E (101 eyes) retinoblastoma in at least one eye from January 1, 2006 to December 31, 2016 using the Los Angeles (LA) Classification System (no tumour size criteria for Group E). The 111 Group D tumours were then reclassified to Group E using 10, 12, 14, 16, 18 mm tumour size criteria, as determined by ultrasound or magnetic resonance imaging dimensions.

RESULTS

For eyes in the original LA classification, 66.7% of Group D and 10.5% of Group E eyes undergoing globe preservation therapy avoided enucleation or radiotherapy (p < 0.0001; median follow-up of 33.0 months). In the LA classification, 8.5% of Group D and 26.3% of Group E enucleated globes had HE histopathologic features (p = 0.0065). When Group D eyes with tumours meeting the size criteria were reclassified to Group E, 65.7-74.4% of Group D and 16.1-36.7% of Group E eyes avoided enucleation or radiotherapy. Applying the tumour size criteria, 0-10.9% of Group D and 20.7-23.8% of Group E eyes had HE histopathologic features.

CONCLUSION

Our retrospective analysis suggests that a large tumour size criteria for Group E retinoblastoma have no clinical basis, given that the LA classification system provided the greatest separation in globe salvage rates between Group D and E eyes. The LA classification system was also able to show a statistically significant difference in the rates of HE histopathologic features between Group D and E eyes. To avoid discrepancies in the literature, we recommend that centres use one uniform system for classifying advanced intraocular retinoblastoma.

Trends in Radiation Practices for Female Ocular Oncologists in North America: A Collaborative Study of the International Society of Ocular Oncology

Background

The aim of this study was to determine the known radiation exposure, attitudes, and consequent risk modifications among female ocular oncologists in North America who routinely administer radioactive plaque brachytherapy treatment and are members of the International Society of Ocular Oncology.

Methods

Nineteen female ocular oncologists completed an anonymous 17-question radiation exposure survey.

Results

Eleven of the participants chose to routinely wear lead protection during surgery; 8 did not. Fifteen of 19 participants reported using an unloaded "nonactive" template to prepare for plaque implantation. During pregnancy, 11 of 13 participants continued to perform plaque brachytherapy. Eight of these 11 undertook measures to decrease radiation exposure self-reported as lead wear and other. The average reported anxiety regarding fertility was 2.1 (SD, 2.2) on a scale from 1 to 10.

Conclusion

This study corroborates prior literature that surgeons' exposure to radiation during plaque brachytherapy is minimal. Nonetheless, there remains some anxiety regarding exposure risk to women, due to potential effects on fertility and fetal health. We found variability in exposure monitoring, required training, and precautions during pregnancy amongst this group of surgeons. Improved education and clearer pregnancy guidelines may equip female ocular oncologists with optimal knowledge regarding risk of radiation exposure.

Exon skipping restores dystrophin expression, but fails to prevent disease progression in later stage dystrophic dko mice

Antisense therapy with both chemistries of phosphorodiamidate morpholino oligomers (PMOs) and 2'-O-methyl phosphorothioate has demonstrated the capability to induce dystrophin expression in Duchenne muscular dystrophy (DMD) patients in phase II-III clinical trials with benefit in muscle functions. However, potential of the therapy for DMD at different stages of the disease progression is not understood. In this study, we examined the effect of peptide-conjugated PMO (PPMO)-mediated exon skipping on disease progression of utrophin-dystrophin-deficient mice (dko) of four age groups (21-29, 30-39, 40-49 and 50+ days), representing diseases from early stage to advanced stage with severe kyphosis. Biweekly intravenous (i.v.) administration of the PPMO restored the dystrophin expression in nearly 100% skeletal muscle fibers in all age groups. This was associated with the restoration of dystrophin-associated proteins including functional glycosylated dystroglycan and neuronal nitric synthase. However, therapeutic outcomes clearly depended on severity of the disease at the time the treatment started. The PPMO treatment alleviated the disease pathology and significantly prolonged the life span of the mice receiving treatment at younger age with mild phenotype. However, restoration of high levels of dystrophin expression failed to prevent disease progression to the mice receiving treatment when disease was already at advanced stage. The results could be critical for design of clinical trials with antisense therapy to DMD.

Pluronic-PEI copolymers enhance exon-skipping of 2'-O-methyl phosphorothioate oligonucleotide in cell culture and dystrophic mdx mice

A series of small-size polyethylenimine (PEI)-conjugated pluronic polycarbamates (PCMs) have been investigated for the ability to modulate the delivery of 2'-O-methyl phosphorothioate RNA (2'-OMePS) in vitro and in dystrophic mdx mice. The PCMs retain strong binding capacity to negatively charged oligomer as demonstrated by agarose gel retardation assay, with the formation of condensed polymer/oligomer complexes at a wide-range weight ratio from 1:1 to 20:1. The condensed polymer/oligomer complexes form 100-300 nm nanoparticles. Exon-skipping effect of 2'-OMePS was dramatically enhanced with the use of the most effective PCMs in comparison with 2'-OMePS alone in both cell culture and in vivo, respectively. More importantly, the effective PCMs, especially those composed of moderate size (2k-5kDa) and intermediate hydrophilic-lipophilic balance (7-23) of pluronics, enhanced exon-skipping of 2'-OMePS with low toxicity as compared with Lipofectamine-2000 in vitro or PEI 25k in vivo. The variability of individual PCM for delivery of antisense oligomer and plasmid DNA indicate the complexity of interaction between polymer and their cargos. Our data demonstrate the potential of PCMs to mediate delivery of modified antisense oligonucleotides to the muscle for treating muscular dystrophy or other appropriate myodegenerative diseases.

Pancreatic endocrine neoplasms: a current update on genetics and imaging

Pancreatic endocrine neoplasms are rare pancreatic tumours that may occur sporadically or as part of inherited syndromes such as multiple endocrine neoplasia-1 syndrome, von Recklinghausen disease, von Hippel-Lindau syndrome and tuberous sclerosis complex. Recent advances in the genetics and pathology of hereditary syndromes have provided valuable insights into the pathophysiology and biology of sporadic pancreatic endocrine neoplasms. Evolving molecular data on the biology of these neoplasms have the potential for diagnostic, therapeutic and prognostic use.

Quality of life in patients with age-related macular degeneration: results from the VISION study

PURPOSE

To assess the impact of treatment with pegaptanib sodium vs usual care on vision-related quality of life (VRQoL) in patients with age-related macular degeneration (AMD).

METHODS

VRQoL was a secondary end point in the trial, a prospective, randomized, double-masked, multicentre, dose-ranging study. Three doses of pegaptanib (0.3, 1, and 3 mg) were compared with usual care with respect to changes in VRQoL as indicated by the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ 25), administered at baseline and weeks 30 and 54. Four of the NEI-VFQ 25 domains were prospectively designated as primary: near vision, distance vision, role limitations, and dependency. Between-group differences were assessed using an analysis of covariance model with age, gender, and baseline score as covariates.

RESULTS

NEI-VFQ 25 data were available for 569 subjects. At week 54, improvements in the distance vision and role limitations domains were greater in pegaptanib than usual care arms. No substantial increase in ocular pain was noted in pegaptanib-treated patients. No clear superiority of any particular dosage strength of pegaptanib was demonstrated, and no significant differences or trends favoured usual care on any domain score or the NEI-VFQ 25 composite score. The greatest VRQoL benefit was seen in responders (lost<3 lines) to treatment.

CONCLUSION

The VISION trial provided evidence of trends in quality-of-life benefit associated with effective treatment of AMD using pegaptanib. Treatment with pegaptanib is expected to contribute significantly to VRQoL improvement for responder patients.

KAtex Test for the Detection of Urinary Antigens in Visceral Leishmaniasis Patients of Nepal

The rapid detection of parasitic antigens in body fluid including urine by immunological tests such asKAtex has been a valuable addition to clinical medicine. Existing method of microscopic bone-marrowexamination and immunological test for antigen –enzyme-linked immunosorbent assay (ELISA) test forvisceral leishmaniasis antigen are difficult to perform in the field, and this has limited use in rural areas ofendemic countries like Nepal. In this study we have tested 276 urine samples from visceral leishmaniasispatients from different endemic areas of Nepal. Sixty-seven patients (24.3%) were found KAtex positive.The clinical picture of these patients was compared with the KAtex test and additional laboratory findings,knowledge, attitude and behaviour were assessed. High rate of KAtex positive (97.4%) was found in bonemarrow confirmed patients with high degrees of sensitivity and specificity. Hence the study confirmed thatthe KAtex test is suitable for the confirmation of suspected cases in the field and hospital where bonemarrowfacilities are limited or where there is a lack of trained manpower as well as microscopic diagnosisis not available.ORIGINAL ARTICLE Journal of Nepal Medical Association 2003; 42: 191-195Sherchand J B*, Shah S N*, Hommel M**Key Words: Rapid diagnostic test, urinary antigen, visceral leishmaniasis, Nepal.

A benefit-based copay for prescription drugs: patient contribution based on total benefits, not drug acquisition cost

Several managerial mechanisms have been used by managed care organizations to affect prescription drug utilization and related expenditures. Some efforts have focused on monitoring clinical conditions, drug use, and compliance, whereas other efforts have focused on consumer cost sharing and changing product-mix. Efforts focusing on improving quality of care by identifying untreated patients or by enhancing compliance can lead to appropriately increased drug costs, although perhaps with reduced overall medical expenditures. In contrast, the mechanisms implemented to constrain drug costs raise concerns regarding missed opportunities to enhance clinical outcomes, and the possibility of higher medical expenditures. Cost sharing plays a critical role in defining the pharmaceutical benefit. To balance the demands for access to pharmaceuticals with pressures to constrain costs, levels of cost sharing must be set in a manner that achieves appropriate clinical and financial outcomes. Modern multitier systems often base patient contributions on drug acquisition cost, and often do not consider medical necessity as a coverage criterion. Using an alternative approach, the benefit-based copay, patient contributions are based on the potential for clinical benefit, taking into consideration the patient's clinical condition. For any given drug, patients with a high potential benefit would have lower copays than patients with a low potential benefit. Implementation of such a system would provide a financial incentive for individuals to prioritize their out-of-pocket drug expenditures based on the value of their medications, not their price.

Specific repression of beta-globin promoter activity by nuclear ferritin

Developmental hemoglobin switching involves sequential globin gene activations and repressions that are incompletely understood. Earlier observations, described herein, led us to hypothesize that nuclear ferritin is a repressor of the adult beta-globin gene in embryonic erythroid cells. Our data show that a ferritin-family protein in K562 cell nuclear extracts binds specifically to a highly conserved CAGTGC motif in the beta-globin promoter at -153 to -148 bp from the cap site, and mutation of the CAGTGC motif reduces binding 20-fold in competition gel-shift assays. Purified human ferritin that is enriched in ferritin-H chains also binds the CAGTGC promoter segment. Expression clones of ferritin-H markedly repress beta-globin promoter-driven reporter gene expression in cotransfected CV-1 cells in which the beta-promoter has been stimulated with the transcription activator erythroid Krüppel-like factor (EKLF). We have constructed chloramphenicol acetyltransferase reporter plasmids containing either a wild-type or mutant beta-globin promoter for the -150 CAGTGC motif and have compared the constructs for susceptibility to repression by ferritin-H in cotransfection assays. We find that stimulation by cotransfected EKLF is retained with the mutant promoter, whereas repression by ferritin-H is lost. Thus, mutation of the -150 CAGTGC motif not only markedly reduces in vitro binding of nuclear ferritin but also abrogates the ability of expressed ferritin-H to repress this promoter in our cell transfection assay, providing a strong link between DNA binding and function, and strong support for our proposal that nuclear ferritin-H is a repressor of the human beta-globin gene. Such a repressor could be helpful in treating sickle cell and other genetic diseases.

Intramedullary screw fixation of proximal fifth metatarsal fractures: a biomechanical study

Intramedullary screw fixation is a popular technique for treatment of proximal fifth metatarsal fractures. The purpose of this study was to compare the fixation rigidity of a 5.5 mm partially threaded cannulated titanium screw, with presumed superior endosteal purchase, to a similar 4.5 mm screw. Acute fifth metatarsal fractures were simulated in cadavers, stabilized with intramedullary screws, and loaded to failure in three-point bending. The initial failure loads for the metatarsals fixed with 4.5 mm and 5.5 mm screws were not significantly different (332.4 N vs. 335.2 N, respectively), nor were the ultimate failure loads (849.8 N vs. 702.2 N, respectively). Based upon our results, maximizing screw diameter does not appear to be critical for fixation rigidity and may increase the risk of intraoperative or postoperative fracture.

The post-prandial state and macrovascular disease: relevance to diabetes mellitus

There is increasing evidence that the post-prandial state is an important contributing factor to the development of atherosclerosis. In non-diabetic subjects the atherosclerotic risk factors comprised in the categories of lipids, coagulation system and endothelial function may be adversely modified in the post-prandial phase. The generation of an oxidative stress may be the common pathway through which eating may induce these alterations. In diabetic patients these phenomena may be amplified by post-prandial hyperglycemia. There is a growing thought that diabetes is a cardiovascular disease.

Lipid analog with 2-nitrophenol trigger designed for liposome fusion at physiological pH

A novel lipid analog with two long alkyl (C16) chains, an aspartate skeleton, a connecting alkyl (C8) chain, and 2-nitrophenol trigger group is synthesized by an efficient synthetic route, which can induce liposome fusion at physiological pH.

Coronary artery disease in women: a silent killer

Coronary Artery Disease (CAD) is the leading cause of death and disability among post-menopausal women. Contrary to popular belief, women are at a much greater risk for CAD than for breast cancer. For instance, a 50-year-old female faces a 46 percent risk of CAD and 31 percent risk of CAD mortality. In contrast, her probability of developing and dying from breast cancer is only 10 percent and 3 percent, respectively. In comparison to the other cardiovascular diseases such as mitral valve prolapse, peripartum cardiomyopathy, and eclempsia, CAD is most associated with mortality in women. In fact, one in three women die from CAD in this country.

Influence of microbial concentration on the rheology of non-Newtonian fermentation broths

The objective of this study was to quantify the effect of fungal biomass concentration on the rheology of non-Newtonian fermentation systems. Batch fermentations of Penicillium chrysogenum were carried out with glucose as the sole carbon source. The flow behavior of the system was characterized at various fermentation times and was adequately described by the power-law model. The apparent viscosity of the fermentation broth was significantly affected by biomass concentrations in the fermenter. Fermentation broths containing 17.71 g/l biomass as dry weight were characterized by an apparent viscosity of 0.25 Pa s at a shear rate of 50 s-1. Microbial concentration also affected the power-law flow-behavior index and the consistency index. The value of the consistency index ranged from 0.002 Pa sn at a biomass concentration of 0.1 g/l to 6.14 Pa sn at a biomass concentration of 17.71 g/l. The flow-behavior index decreased from an initial value of 1 to a final value of 0.17. Simple empirical correlations have been proposed to quantify the dependence of the power-law parameters on fungal biomass concentration. Experimental data obtained in this study were accurately described by these correlations. The general applicability of these relationships was tested, using previously published rheological data on Aspergillus awamori and Aspergillus niger fermentation broths, and good agreement was seen between experimental data and the predictions from the empirical correlations.

Arylsulfatase A and beta-galactosidase activities in leukocytes and lymphocytes from normal and psychiatric subjects. Effects of blood-processing delay and interleukin-2 stimulation

Arylsulfatase A (ASA) and cerebroside-beta-galactosidase activities in leukocytes serve as a diagnostic tool for determining the presence of metachromatic leukodystrophy and globoid cell leukodystrophy, respectively. It has not been demonstrated whether a delay in blood processing and the presence of mixed cell types in different proportions in leukocytes affect the activities of the two enzymes in these cells. We have in the present study determined the specific activity in leukocytes and lymphocytes (T-cells) prepared from blood samples processed immediately after, 4, and 24 h after collection. In order to determine whether the enzyme activities in lymphocytes reflect expression of genetic trait, and not environmental or "state" influence, the activities of the two enzymes in interleukin 2-stimulated T-cells and resting T-cells were compared. A delay of up to 24 h in blood processing did not significantly change the specific activities of the two enzymes in both leukocytes and lymphocytes. The specific activity of ASA and beta-galactosidase in lymphocytes was 1.4-1.8 times that in leukocytes. The activities of the two enzymes in interleukin 2-stimulated T-cells did not differ from those in resting T-cells. These results indicate that blood-processing delay had no significant effects on ASA and beta-galactosidase activity. The data further indicate that the ASA and beta-galactosidase activity in interleukin 2-stimulated T-cells was not significantly different from resting lymphocytes from either normal or psychiatric subjects exposed to various medications. The activity levels in lymphocytes from psychiatric subjects thus reflect expression of genetic trait, rather than environmental or state influence.

Cocaine exposure prebreeding to weaning: maternal and offspring effects

In a model emphasizing prebreeding cocaine administration, rats exposed to cocaine (50 mg/kg) daily were compared to saline-injected and noninjected controls with respect to weight changes, food and water intake, maternal behavior, offspring weight, and activity. During the first 21 days cocaine-treated dams lost weight, while the control dams gained. Throughout gestation and the first 14 days of lactation all groups gained weight, but the cocaine-exposed dams never completely recovered from the initial anorectic effect. Except during the first week of exposure, cocaine dams ate and drank more than the normal controls and drank more than the saline group. During gestation there was no difference in food intake, although the cocaine dams continued to drink more than controls. During lactation there were no differences in food and water consumption across groups. However, the cocaine dams exhibited more nursing behavior. From birth to day 21, the offspring of cocaine-treated dams were smaller than those of either control group. By 51 days of age, group differences had disappeared. Cocaine-exposed pups and saline offspring tested at days 28 and 85 were more active than those of noninjected controls. The results indicate that administration of cocaine for a period prior to breeding and during gestation and lactation, a protocol which closely resembles human drug abuse patterns, is more devastating than the administration during gestation.

Polyorchidism discovered as testicular torsion

We report on a case of polyorchidism that presented as testicular torsion. A brief history and review of the literature is also presented. Of the 47 cases reported, this patient is the youngest.

Effect of serum lipoproteins on growth and sterol synthesis in cultured rat brain glial cells

Cells dissociated from brains of 1-day-old rats were cultured in medium containing either lipoprotein-deficient serum (LPDS) or LPDS plus various lipoprotein fractions. Increases in number of cells and in DNA content served as a measure of cell growth. Cholesterol synthesis was measured from the incorporation of [14C]acetate into total nonsaponifiable lipids and digitonin-precipitable sterols, and from the activity of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase. The data indicated that cholesterol biosynthesis from acetate was reduced in cells cultured in medium containing either LPDS plus low-density lipoproteins (LDL), high-density lipoproteins (HDL), or total lipoproteins (LP) and that this reduction was accompanied by a reduction in the activity of the HMG CoA reductase and an increase in the esterified sterol content. The reduction in cholesterol synthesis from acetate was maximal in cells cultured in the presence of HDL, whereas the maximal reduction in the activity of HMG CoA reductase occurred in cells cultured in the presence of LP. The presence of LDL or LP in the culture medium enhanced the cell growth but the presence of HDL did not. Esterified sterol content was highest in cells cultured in the medium containing LPDS plus LP and was not detected in cells cultured in LPDS medium. It is inferred from these data that rat brain glial cells in culture are able to utilize cholesterol in lipoproteins, that the presence of LDL in the medium enhances cell growth, and that reduced cholesterol synthesis in the presence of lipoproteins may occur at the HMG CoA reductase step as well as at some other step(s).

Cholesterol ester hydrolase(s) in mammalian brain: is there a myelin-specific cholesterol ester hydrolase?

The present study compared the properties of cholesterol ester hydrolase(s) in myelin and microsomes from rat, mouse and human brain. The results indicated that the enzyme activity in both myelin and microsomes from rat, mouse and human brain was optimal at pH 6.5 and required Triton X-100 for optimal activity. The enzyme activity in myelin was 3- to 4-fold higher in the presence of Triton X-100 than taurocholate. Addition of phosphatidyl serine enhanced (2 to 4 fold) the hydrolase activity in both myelin and microsomes. The properties of the enzyme in solubilized preparation of myelin were also similar to the properties of the enzyme in partially delipidated and solubilized preparations of microsomes. The activity was again optimal at pH 6.5, required Triton X-100 for optimal activity and was stimulated by phosphatidyl serine. These results indicate that the properties of cholesterol ester hydrolase in myelin are similar to those of the microsomal enzyme and that this is true for the fractions from both human and rodent brain. The data thus lead us to believe that the hydrolase activity in mammalian brain myelin and microsomes may reflect the distribution of a single enzyme in the two fractions rather than two distinct enzymes, one being specific to each fraction.

Growth and lipid composition of rat brain glial cells cultured in lipoprotein deficient serum

The purpose of this study was to examine the effects of substituting lipoprotein deficient serum (LPDS) for complete fetal calf serum (FCS) in culture media on the growth and lipid composition of cells dissociated from 1 to 2-day-old rat brain. The results show that in FCS cultures DNA, protein and all lipids increase with an increase in the number of days in culture. Substitution of LPDS for FCS in the culture media caused a slower increase in each of these constituents. Esterified cholesterol remained unaltered with time in LPDS cultures but increased continuously in FCS cultures. Substitution of LPDS for FCS reduced the DNA:protein ratio, and unesterified cholesterol:phospholipid ratio but the protein:phospholipid ratio and the proportion of individual phospholipids were not affected. The data indicate that removal of low density lipoprotein (LDL) from serum used in culture media reduces cell proliferation and causes alterations in cellular lipid composition specifically ratio of cholesterol:phospholipids.

Metabolism of intracerebrally injected mevalonate in brain of suckling and young adult rats

We have investigated the in vivo metabolism via sterol and nonsterol pathways of intracerebrally injected mevalonate (MVA) in brains from suckling (10-day-old) and young adult (60-day-old) rats. Results of our study indicated that increasing the amounts of MVA injected increased MVA incorporation into all the lipid fractions examined. The incorporation of MVA into nonsaponiable lipids (NSF) and digitonin precipitable sterols (DPS) was similar in brains from adult and suckling rats. In brain tissue from both suckling and young adult rats the synthesis of dolichol from MVA varied with the amounts of MVA injected. Significant amounts of MVA were recovered in phosphorylated and free polyprenols (farnesol and geraniol) in brain tissue from rats of both ages. Also in both groups of animals, the amounts of MVA incorporated in phosphorylated and free farnesol were higher than the amounts recovered in either, phosphorylated or free geraniol. The amounts of MVA incorporated into the prenoic/fatty acid fraction by brain tissue from both suckling and young adult rats were less than 1% of the total MVA incorporated (nonsaponifiable and saponifiable lipids). Incorporation of MVA into the prenoic/fatty acid fraction by brain tissue was higher in suckling than in young adult rats. These data indicate that the brain tissue from suckling and young adult rats do not differ in their capacity to metabolize MVA into squalene and sterols and that in brain, metabolism of MVA by a shunt pathway is minimal. This suggests that in vivo regulation of cholesterol synthesis during brain development must occur at a step(s) in the sterol synthetic pathway prior to mevalonate, and that metabolism of mevalonate by shunt pathway did not play a role in the developmental regulation of brain sterol synthesis. The data also suggest that in both groups of animals the synthesis of squalene by synthetase may in part control brain sterol synthesis and the synthesis of dolichol is regulated by MVA concentration in the tissue.

Prevalence of partial cerebroside sulfate sulfatase (arylsulfatase A) defect in adult psychiatric patients

Metachromatic leukodystrophy (MLD) is a disease caused by a deficiency of the enzyme sulfatide sulfatase, also known as arylsulfatase A (ASA). We compared the activity of this enzyme in adult psychiatric patients and normal volunteers using nitrocatechol sulfate (ASA-NCS) and cerebroside sulfate (ASA-CS) as substrates. Our results showed that ASA-NCS activity in urine and leukocytes was significantly lower in psychiatric than in normal individuals, but that there were no differences between these two groups in the sulfatide excretion in urine or the ASA-CS activity in leukocytes. There was no correlation between enzyme activity in urine and in leukocytes, indicating that activity in urine does not truly reflect the levels of the enzyme in tissues. The correlation between ASA-NCS and ASA-CS activity in leukocytes was poor (0.51 for psychiatric patients and 0.59 for normals), suggesting that for a valid measure of the enzyme activity the assays should be carried out with CS as substrate. Results of our study also indicate that in 39 of the 145 psychiatric patients studied, the ASA-CS activity in leukocyte was less than 4 nmoles/mg protein/hr, which is below 50% of the normal means, whereas only one of the 30 normal subjects had a value this low. The presence of low levels of ASA-CS activity in a significantly large number of adult patients with varying psychiatric manifestations suggests that such patients may be asymptomatic carriers of the sulfatidase defect (heterozygotes for MLD), and that behavioral and functional disturbances in these patients may at least in part be related to sulfatidase deficiency. The significance of the ASA-NCS abnormality (reduction) in psychiatric patients is unclear.

Failure of 5-hydroxytryptophan to modulate brain stem auditory evoked responses in myelin deficient mutant qk mice

The effect of 5-hydroxytryptophan (5-HTP) on brain stem auditory evoked response (BAER) amplitude in Quaking (qk) and normal littermate mice was examined. Administration of 5-hydroxytryptophan (5-HTP) (75 mg/kg, i.p.) to normal mice increased the amplitude of BAER peaks I, II, and III but had no effect on peak IV. In qk mice, however, 5-HTP did not affect the amplitude of any BAER peaks. Our data indicate that although 5-HTP increased BAER amplitude in normal mice, it failed to modulate BAER in qk mice. These findings are consistent with the possibility that 5-HTP receptor sites associated with myelin basic protein may be reduced in the myelin-deficient mutant qk mice.

Effect of hyperphenylalaninemia induced during suckling on brain DNA metabolism in rat pups

We studied DNA metabolism (synthesis and degradation) in brain to investigate the effect of hyperphenylalaninemia induced in rats by treatment with PCPA or alpha MPA plus PHE during suckling (4th-20th days of postnatal age) on cell proliferation and naturally occurring cell death. The incorporation of 14C in DNA as percent of total radioactivity in the tissue, 30 min after administration of [14C]thymidine served as a measure of DNA synthesis in vivo, and the amount of radioactivity recovered in DNA as percent of total 14C in the tissues of 21 day old rats, injected with [14C]thymidine on 2nd day after birth, indicated the turnover (degradation) of DNA. The results showed that the DNA content of cerebellum as well as cerebrum was reduced by treatment with PCPA plus PHE, while treatment with alpha MPA plus PHE had no effect on DNA content in cerebellum but reduced the levels in cerebrum. Treatment with PCPA or alpha MPA plus PHE reduced the synthesis of DNA in cerebrum of 11 day old rats but not in 21 day old rats, and the treatments did not affect DNA synthesis in cerebellum of either 11 or 21 day old rats. The turnover (degradation) of DNA was increased in both cerebellum and cerebrum from rats treated with PCPA plus PHE but alpha MPA plus PHE treatment did not alter the DNA turnover either in cerebellum or in cerebrum. The activity of acid DNase was reduced in both cerebellum and cerebrum from 11 as well as 21 day old rats treated with PCPA plus PHE, but the enzyme activity was not altered in the tissues from rats of both ages treated with alpha MPA plus PHE. The data thus indicate that in rats treated with PCPA plus PHE the reduction in cerebral DNA levels occurs due to reduced synthesis and/or increased turnover (degradation) of DNA but that the reduction in cerebellar DNA may occur only as a result of increased turnover (degradation), and that in rats treated with alpha MPA plus PHE the reduction in cerebral DNA must occur due to reduced synthesis. This suggests that treatment of rats with PCPA plus PHE during suckling inhibits cell proliferation and/or increases naturally occurring cell death in both cerebellum and cerebrum while treatment with alpha MPA plus PHE inhibits only cell proliferation and in cerebrum alone.

Brain DNA metabolism in myelin deficient mutant jp, jpmsd and qk mice

We studied metabolism of brain DNA in three myelin deficient mutants qk, jp and jpmsd mice. The DNA content, the in vivo incorporation of [14C]thymidine in DNA and the activity of acid DNase in tissues (cerebellum and cerebrum) from normal littermates and affected mice were compared. The results showed that neither the DNA content, the incorporation of [14C]thymidine in DNA nor the activity of acid DNase in brain were altered in qk affected mice. In jpmsd mice, however, the DNA content as well as the incorporation of thymidine in DNA were reduced in both cerebellum and cerebrum, but the activity of acid DNase was reduced in cerebrum only. In jp mice, although the DNA content was reduced in both cerebellum and cerebrum, the incorporation of thymidine in DNA and the activity of acid DNase were reduced in cerebrum only. The data suggest a) that in qk mutants DNA metabolism and hence cell (glial) proliferation is not affected; b) that in jpmsd mutants DNA synthesis, and thus the cell proliferation is reduced in cerebellum as well as in cerebrum of the affected mice and c) that in jp mutants the synthesis of DNA and the cell proliferation is reduced in cerebrum but not in cerebellum.

Presynaptic tyrosine availability in the phenylketonuric brain: a hypothetical evaluation

From measured effects of amino acids on synaptosomal tyrosine uptake and from published data on human CNS levels of amino acids hypothetical calculations were made to compare CNS tyrosine availability for catecholamine synthesis in the hyperphenylalaninemic and non-hyperphenylalaninemic condition. These calculations indicate an approximately two-fold reduction in the availability of tyrosine in phenylketonuria that is due solely to a reduction in CNS tyrosine alone.