Correlation of antibody titres induced by vaccination with protection in mouse typhoid

The ELISA method was used to titrate the humoral immune response in vaccinated mice. When mice were given two doses of a heat-killed salmonella vaccine 6 days apart, there was a steady but low-level increase of antibody synthesis. In contrast, if a booster vaccination was administered 21 days after the primary inoculation, the anamnestic response produced a significantly greater antibody titre, rapidly reaching its peak within 10 days. Such a heightened humoral response induced in the genetically susceptible C57BL/6J mice also coincided with effective protection against an otherwise lethal challenge with Salmonella typhimurium.

Hypopigmentation in Angelman syndrome

Chromosome region 15q is thought to contain one or more genes that are important for melanin pigment synthesis in the hair, skin, and eyes. Hypopigmentation has been identified in the Prader-Willi (PWS) and Angelman (AS) syndromes. We have examined 6 individuals with AS to further characterize the pigment pattern in this condition. The age of the 5 girls and one boy ranged from 2.4 to 7.0 years. None had obvious albinism. Hair color ranged from light blond to brown. Skin was type I in 3 and type II in 3. Eye changes included nystagmus in 2, strabismus in 4, and reduced retinal pigment in 5. The mean hairbulb tyrosinase activity was 0.37 +/- 0.44 pmol/hb/120 min for the individuals with AS, with a range of 0.00 to 1.13 (normal brown control 1.49 +/- 0.79, normal blond control 1.50 +/- 0.85). Electron microscopic examination of hairbulb melanocytes showed normal melanosome and melanocyte architecture and number, but reduced melanin formation, with many stage II and III premelanosomes but few stage IV fully melanized melanosomes. Hypopigmentation characterized by light skin, reduced retinal pigment, low hairbulb tyrosinase activity, and incomplete melanization of melanosomes is part of the phenotype of AS, and is similar to that found in PWS.

Death without warning? A clinical postmortem study of suicide in 43 Israeli adolescent males

Forty-three consecutive Israeli male suicides, 18 to 21 years of age, that occurred during compulsory military service were studied using preinduction assessment data, service records, and extensive postmortem interviews with family and peers. At preinduction, subjects, as a group, appeared above average in intelligence, physical fitness, and measures predictive of successful adaptation to military service. Active duty performance was generally satisfactory. Ascertained post mortem, 53.5% met formal criteria for major depressive disorder; most cases, however, appeared recent and reactive. Narcissistic and/or schizoid traits were common. Substance abuse was absent and antisocial personality disorder was rare (4.7%). Furthermore, in eight patients (18.6%) no Axis I diagnosis could be made; half of these also lacked any significant Axis II pathology. These findings, at partial variance with US studies, suggest a complex relationship between suicide and mental disorder. The striking failure of intensive screening and preventive measures to prevent these suicides highlights unresolved questions of etiology and intervention.

Molecular basis of type I (tyrosinase-related) oculocutaneous albinism: mutations and polymorphisms of the human tyrosinase gene

Type I (tyrosinase related) oculocutaneous albinism (OCA) results from mutations of the tyrosinase gene on chromosome 11q that lead to reduced or absent melanin pigment synthesis. The phenotype of Type I OCA is broad, ranging from a total lack to only a moderate reduction of melanin, and the phenotypic variation is associated with different mutant alleles at the tyrosinase locus. A total of 36 mutations have been identified in Type I OCA including 24 missense, 4 nonsense, and 8 frameshift mutations. The majority of affected individuals have been compound heterozygotes with different maternal and paternal alleles. Six polymorphic sites for haplotype analysis have been identified in the tyrosinase gene including 2 in the promoter region, 2 in the coding region associated with alternative amino acids in the protein, and 2 RFLPs in the first intron.

A frequent tyrosinase gene mutation associated with type I-A (tyrosinase-negative) oculocutaneous albinism in Puerto Rico

We have determined the mutations in the tyrosinase gene from 12 unrelated Puerto Rican individuals who have type I-A (tyrosinase-negative) oculocutaneous albinism (OCA). All but one individual are of Hispanic descent. Nine individuals were homozygous for a missense mutation (G47D) in exon I at codon 47. Two individuals were heterozygous for the G47D mutation, with one having a missense mutation at codon 373 (T373K) in the homologous allele and the other having an undetermined mutation in the homologous allele. One individual with negroid features was homozygous for a nonsense mutation (W236X). The population migration between Puerto Rico and the Canary Islands is well recognized. Analysis of three individuals with OCA from the Canary Islands showed that one was a compound heterozygote for the G47D mutation and for a novel missense mutation (L216M), one was homozygous for a missense mutation (P81L), and one was heterozygous for the missense mutation P81L. The G47D and P81L missense mutations have been previously described in extended families in the United States. Haplotypes were determined using four polymorphisms linked to the tyrosinase locus. Haplotype analysis showed that the G47D mutation occurred on a single haplotype, consistent with a common founder for all individuals having this mutation. Two different haplotypes were found associated with the P81L mutation, suggesting that this may be either a recurring mutation for the tyrosinase gene or a recombination between haplotypes.

Analysis of mutations in the copper B binding region associated with type I (tyrosinase-related) oculocutaneous albinism

Mutations of the tyrosinase gene are responsible for type I (tyrosinase-related) oculocutaneous albinism (OCA), an autosomal recessive genetic syndrome with a broad phenotypic spectrum. Mutant tyrosinase alleles can be associated with no melanin synthesis (I-A, tyrosinase-negative OCA), small to moderate amounts of melanin (I-B, yellow OCA) or unusual pigment patterns (I-TS, temperature-sensitive OCA). A total of 26 mutations of this gene have been described in type I OCA. Analysis of all known mis-sense mutations (n = 17) shows that most cluster in three areas of the coding region. Two clusters involve the copper A or copper B binding sites and may disrupt the metal ion-protein interaction necessary for enzyme function and the third cluster is located in exon I. Computer modeling of the secondary structure of the copper binding regions based on homology with the known crystal structure of hemocyanin show that they both consist of two alpha helices containing three histidine ligands that complex to a single copper atom. Mutations in the copper B binding region lie in the region between the two alpha helices that consists of a loop structure. These mutations may affect tyrosinase activity by either altering the position of the alpha helical domains and thus preventing proper copper binding to the histidine ligands, or affecting a catalytic or substrate binding site located between the two alpha helical domains.

Molecular analysis of type I-A (tyrosinase negative) oculocutaneous albinism

Type I oculocutaneous albinism (OCA) is caused by the reduction in or absence of activity of tyrosinase in melanocytes in skin, hair, and the eyes, the result of mutations of the tyrosinase gene. To date, a total of 22 unique mutations in the coding region of tyrosinase have been described in the literature. In this report we present 5 additional mutations of the tyrosinase gene associated with type I-A OCA in four individuals, including 2 missense, 1 frameshift and 2 nonsense mutations, and review the relevant literature on all published mutations. Analysis of the distribution of all identified missense mutations (n = 17) shows that most cluster in three areas of the gene and involve amino acids conserved between humans and the mouse. Two clusters involve the copper A and copper B binding sites and may disrupt the metal ion-protein interaction necessary for enzyme function. The third cluster in exon I could represent a functional domain important in enzyme function such as the tyrosine or the dihydroxyphenylalanine (DOPA) binding site of the enzyme. Small deletions or insertions resulting in frameshift mutations and nonsense mutations are distributed throughout the coding region and do not appear to cluster.

Double-blind, crossover trial of fluoxetine and placebo in children and adolescents with obsessive-compulsive disorder

Rigorously designed clinical trials have demonstrated the efficacy and safety of fluoxetine in adults with major depressive disorder and obsessive-compulsive disorder (OCD) but not in patients below 18 years old. This report describes a randomized, double-blind, placebo-controlled, fixed-dose (20 mg qd) trial of fluoxetine in 14 children and adolescents with OCD, ages 8 to 15 years old; the study was 20 weeks long with crossover at 8 weeks. Obsessive-compulsive symptom severity was measured on the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) and the Clinician's Global Impression-Obsessive Compulsive Disorder scale (CGI-OCD). The CY-BOCS total score decreased 44% (N = 7, p = .003) after the initial 8 weeks of fluoxetine treatment, compared with a 27% decrease (N = 6, p = .13) after placebo. During the initial 8 weeks, the magnitude of improvement for the fluoxetine group significantly exceeded that for the placebo group as measured by the CGI-OCD (p = .01) but not by the CY-BOCS (p = .17). The most common drug side effects were generally well tolerated. The results suggest that fluoxetine is a generally safe and effective short-term treatment for children with OCD.

Site-directed mutagenesis of an amino acid residue in the bacteriophage P2 ogr protein implicated in interaction with Escherichia coli RNA polymerase

The P2 ogr gene encodes a 72-amino-acid protein required for P2 late gene expression. This gene was defined originally by a class of compensatory mutations which overcome the block to P2 late transcription imposed by a host mutation, rpoA109, in the gene encoding the alpha subunit of Escherichia coli RNA polymerase. Spontaneous compensatory ogr mutations substitute a Cys for a Tyr residue at amino acid 42 in the Ogr polypeptide. Using suppression of an ogr amber mutation and site-directed oligonucleotide mutagenesis, we have studied the effect of amino acid substitutions at this position in Ogr. Substitution of charged residues at this site renders Ogr protein inactive, in rpoA+ and rpoA109 strains. While 11 different amino acids are capable of replacing the wild-type Tyr-42 to allow P2 growth to varying degrees in a wild-type E. coli strain, only three of these allow phage growth in strains carrying the rpoA109 mutation. Phages carrying Cys or Ala in place of Tyr-42 gave burst sizes at least as high as P2 ogr+ in a rpoA+ strain; a Gly substitution also allowed P2 to grow in either a rpoA+ or rpoA109 background, but markedly reduced the burst size. These results are consistent with a direct interaction between Ogr and the alpha subunit of E. coli RNA polymerase in positive control of P2 late transcription, and indicate that the block imposed by the rpoA109 mutation is due to steric hindrance.

Effects of enalapril and hydralazine treatment and withdrawal upon cardiovascular hypertrophy in stroke-prone spontaneously hypertensive rats

OBJECTIVE

To test the hypothesis that effects of angiotensin converting enzyme (ACE) inhibitors upon resistance vessel structure are responsible for their ability to cause long-term reduction in blood pressure.

DESIGN

Stroke-prone spontaneously hypertensive (SHRSP) and Wistar-Kyoto (WKY) rats were treated with enalapril or hydralazine from 4 to 15 weeks of age. Effects upon tail-cuff blood pressure, left ventricular hypertrophy and structural indices of the superior mesenteric artery (SMA) and its resistance vessels were assessed at 11 weeks of treatment and up to 11 weeks post-treatment.

METHODS

Left ventricular hypertrophy was assessed by left ventricular weight:body weight ratios. Evidence of vascular structural change was obtained from tissue weight:body weight ratios, levels of RNA, DNA and expression of alpha-actin and elastin messenger (m)RNA.

RESULTS

The effects of enalapril and hydralazine upon left ventricular hypertrophy in SHRSP were consistent with their respective effects upon blood pressure. Both drugs prevented the development of medial hypertrophy in SMA and resistance vessels. This was accompanied by substantial reductions in RNA:DNA ratios. Alpha-actin mRNA levels were not affected by either drug but elastin mRNA levels were reduced by both drugs. During the first 12 days post-treatment there was evidence of structural change in SMA accompanying the increases in blood pressure but importantly not in the resistance vessels.

CONCLUSION

The effects of enalapril upon left ventricular hypertrophy and mesenteric arterial hypertrophy are totally consistent with responses to blood pressure and the persistence of structural changes post-treatment does not underlie the ability of the ACE inhibitors to persistently suppress hypertension.

The mouse pink-eyed dilution gene: association with human Prader-Willi and Angelman syndromes

Complementary DNA clones from the pink-eyed dilution (p) locus of mouse chromosome 7 were isolated from murine melanoma and melanocyte libraries. The transcript from this gene is missing or altered in six independent mutant alleles of the p locus, suggesting that disruption of this gene results in the hypopigmentation phenotype that defines mutant p alleles. Characterization of the human homolog revealed that it is localized to human chromosome 15 at q11.2-q12, a region associated with Prader-Willi and Angelman syndromes, suggesting that altered expression of this gene may be responsible for the hypopigmentation phenotype exhibited by certain individuals with these disorders.

Oculocutaneous albinism: variable expressivity of nystagmus in a sibship

Traditionally, the diagnosis of ocular or oculocutaneous albinism (OCA) is based on a constellation of features including the presence of nystagmus associated with iris transillumination defects, hypopigmentation of the fundus, and hypoplasia of the fovea and optic nerve head. Nystagmus is the most frequent ocular sign for the ascertainment of albinism particularly in individuals who have lightly-pigmented parents. We report two siblings, a male and female, with minimal, if any, pigmentation of skin and hair, iris transillumination defects, blond fundi, and hypoplasia of the foveae and optic nerve heads who were discordant for nystagmus; the diagnosis of OCA was based on the clinical findings. These siblings presumably have the same genetic hypopigmentation defect and demonstrate that nystagmus is not a consistent finding in OCA and may not be an absolute criterion for diagnosis.

Prevalence of hypertension in Kimberley aborigines and its relationship to ischaemic heart disease. An age-stratified random survey

OBJECTIVE

To determine the age-specific prevalence of systolic and diastolic hypertension and of electrocardiographic abnormalities in the Aboriginal population of the Kimberley region of Western Australia.

DESIGN AND SETTING

Age and sex stratified random samples of the Aboriginal population of the Kimberley region were selected and located. Measurements were made of systolic and diastolic blood pressure and electrocardiograms (ECG) were recorded. Hypertension was defined as a systolic blood pressure of 160 mmHg or greater or diastolic blood pressure of 95 mmHg or greater. ECG abnormalities were classified by the Minnesota system.

PARTICIPANTS

Measurements were made on 249 men and 241 women distributed in seven age bands above 15 years and representing 78% of the selected men and 76% of the selected women.

INTERVENTIONS

In addition to ECG and blood pressure, measurements were made of height and weight and information was obtained on medication, smoking, drinking and diet. A sample of venous blood was obtained.

MAIN OUTCOME MEASURES

The data obtained on blood pressure, hypertension and ECG abnormalities were compared with existing data on Caucasian and Aboriginal Australians.

RESULTS

Aboriginal men below the age of 30 years showed particularly high blood pressure compared with Caucasian men. The overall prevalence of hypertension in Aboriginal men 50 years of age and older was 45%. The prevalence of hypertension among Aboriginal women increased sharply from 35 years of age with a maximum between 55 and 65 years. The overall prevalence of hypertension in women 50 years of age and older was 50%. By regression, the average systolic/diastolic blood pressure at 40 years was 137/85 mmHg for men and 135/83 mmHg for women. ECG abnormalities indicating ischaemic heart disease (IHD) were more prevalent in both male and female Aborigines than had been found for Caucasians in 1966. In both sexes IHD and especially code 1.1 indicating myocardial infarct were associated with systolic hypertension.

CONCLUSIONS

The prevalence of both systolic and diastolic hypertension and of probable IHD was two to three times higher in Kimberley Aborigines than in Caucasian Australians. ECG evidence of infarct was significantly related to systolic hypertension in both sexes.

Risk factors for hypertension in Kimberley Aborigines

OBJECTIVE

To determine physical, biochemical and lifestyle factors associated with high blood pressure among Aborigines in the Kimberley region.

DESIGN

Blood pressure and electrocardiographic (ECG) abnormalities in an age and sex stratified random sample of the Aboriginal population were related to other observations and measurements made at the same time specifically for the purpose of these comparisons.

SETTING

A field study in which subjects were interviewed and measurements made mostly in community clinics.

PARTICIPANTS

All 249 men and 241 women from the prevalence study were included although only complete data sets for the various comparisons were analysed.

INTERVENTIONS

A sample of venous blood was obtained in addition to physical measurements and information at interview.

MAIN OUTCOME MEASURES

Statistical analysis of the relationships between blood pressure or hypertension and alcohol consumption, plasma gamma-glutamyl transpeptidase (GGT) activity, use of tobacco, body mass index (BMI, kg/m2) and non-fasted plasma cholesterol level. Hypertension was defined as systolic blood pressure of 160 mmHg or greater or diastolic blood pressure of 95 mmHg or greater.

RESULTS

High blood pressure in Aboriginal men below 30 years was associated both with current drinking status and with circulating GGT level. There was a positive association of diastolic hypertension with consumption of alcohol in middle aged men (30 to 49 years) and in older women. Drinking was highly prevalent among men, especially below 30 years, but was less prevalent among women. Both systolic and diastolic blood pressure were positively related to BMI across the population but obesity (BMI greater than or equal to 30 kg/m2) was highly prevalent only among middle-aged women. Both systolic and diastolic blood pressure were positively and strongly related to plasma cholesterol level independently of the latter's relationship to age and BMI.

CONCLUSION

The high prevalence of drinking among Aboriginal men and of obesity among Aboriginal women involves a risk of hypertension. The association between plasma cholesterol and blood pressure in Aboriginal men and women may be relevant to the demonstrated link between systolic hypertension and ischaemic heart disease.

Behavioral treatment of children and adolescents with trichotillomania

Trichotillomania is a behavior disorder with onset generally in childhood, characterized by repetitive, compulsive pulling out of hair from the scalp, eyebrows, or other parts of the body, often leading to disfigurement. Trichotillomania tends to be persistent and is often resistant to counselling and standard psychiatric care. A systematic behavioral treatment program for children and adolescents and pilot findings with three patients are described. Methodological issues in relation to compliance and assessment are discussed. The relative safety and potential effectiveness of behavioral techniques suggest a useful role for this approach, perhaps in conjunction with pharmacological, family, and other treatment modalities.

Exacerbation of Gilles de la Tourette's syndrome associated with thermal stress: a family study

Gilles de la Tourette's syndrome (TS) is a familial disorder that is often exacerbated by stress or fatigue. Here we present a family of a TS proband that has several members with obsessive-compulsive symptoms, a bleeding disorder, and an unusual sensitivity to heat. The proband, who is affected by all of these traits, was challenged with heat or exercise in climate-controlled conditions and showed a marked increase in the frequency of tics.

Variable expression of vision in sibs with albinism

Oculocutaneous albinism is defined by the presence of cutaneous and ocular hypopigmentation, the latter associated with nystagmus, iris transillumination, reduced retinal pigment, foveal hypoplasia, and misrouting of the optic fibers at the chiasm. The visual acuity is variable but almost always reduced. We report on two brothers with oculocutaneous albinism and markedly different visual acuity. One brother has a visual acuity of 20/100, while the second has similar cutaneous pigmentation and visual acuity of 20/20 and had not previously been recognized as having oculocutaneous albinism. Both brothers have foveal hypoplasia and misrouting of the optic fibers at the chiasm. Biochemical analysis suggests that this is a tyrosinase-related type of oculocutaneous albinism. This study demonstrates that careful observation of foveal development in relatives with normal vision is necessary to detect all individuals with albinism in a family. A suspected diagnosis of albinism may be confirmed when the visual-evoked potentials show excessive decussation of the optic fibers at the chiasm.

Three different frameshift mutations of the tyrosinase gene in type IA oculocutaneous albinism

Mutations in the gene for the pigment-producing enzyme tyrosinase are responsible for type IA (tyrosinase-negative) oculocutaneous albinism (OCA). Most reported mutations have been single base substitutions. We now report three different frameshift mutations in three unrelated individuals with type IA OCA. The first individual has a single base deletion within a series of five guanidines, resulting in a premature stop codon in exon I on one allele and a missense mutation at codon 382 in exon III on the homologous allele. The second individual is a genetic compound of two separate frameshift mutations, including both the same exon I single base deletion found in the first individual and a deletion of a thymidine-guanidine pair, within the sequence GTGTG, forming a termination codon (TAG) in exon I on the homologous allele. The third individual has a single base insertion in exon I on one allele and a missense mutation at codon 373 in exon III on the homologous allele. The two missense mutations occur within the copper Bbinding region and may interfere with either copper binding to the enzyme or oxygen binding to the copper. These five different mutations disrupt tyrosinase function and are associated with a total lack of melanin biosynthesis.

Molecular analysis of an extended family with type IA (tyrosinase-negative) oculocutaneous albinism

We have analyzed the tyrosinase coding region of three individuals having Type IA OCA within an extended family using genomic DNA amplification and dideoxy sequencing. Two of the affected individuals are dizygotic twins. All three have a common missense mutation at codon 81 (Pro----Leu) within exon I. The twins have a second missense mutation at codon 371 (Asn----Thr) within exon III and the third individual has a second missense mutation at codon 47 (Gly----Asp) within exon I. For each of these three individuals, the loss of enzyme function is the result of two different mutations, showing that they are compound heterozygotes of two mutant tyrosinase alleles.

Tyrosinase gene mutations associated with type IB ("yellow") oculocutaneous albinism

We have identified three different tyrosinase gene mutant alleles in four unrelated patients with type IB ("yellow") oculocutaneous albinism (OCA) and thus have demonstrated that type IB OCA is allelic to type IA (tyrosinase negative) OCA. In an inbred Amish kindred, type IB OCA results from homozygosity for a Pro----Leu substitution at codon 406. In the second family, type IB OCA results from compound heterozygosity for a type IA OCA allele (codon 81 Pro----Leu) and a novel type IB allele (codon 275 Val----Phe). In the third patient, type IB OCA results from compound heterozygosity for the same type IB allele (codon 275 Val----Phe) and a novel type IB OCA allele. In a fourth patient, type IB OCA results from compound heterozygosity for the codon 81 type IA OCA allele and a type IB allele that contains no identifiable abnormalities; dysfunction of this type IB allele apparently results from a mutation either well within one of the large introns or at some distance from the tyrosinase gene. In vitro expression of the Amish type IB allele in nonpigmented HeLa cells demonstrates that the Pro----Leu substitution at codon 406 greatly reduces but does not abolish tyrosinase enzymatic activity, a finding consistent with the clinical phenotype.

Thromboxane responsiveness of dog platelets is inherited as an autosomal recessive trait

Most mongrel dogs have platelets that form thromboxane A2 (TXA2) from exogenous arachidonate, but they fail to aggregate or secrete in response to it. In contrast to these TXA2 insensitive (TXA2-) platelets, some dogs have TXA2 sensitive (TXA2+) platelets that aggregate and secrete when stirred with arachidonate. To evaluate the possible genetic basis for this difference, we carried out seven matings of mongrel dogs that yielded 48 viable offspring. Four matings of dogs with TXA2- platelets (presumed genotype TT) including 2 back-crosses, produced 32 pups with TXA2- (TT) platelets and 0 pups with TXA2+ platelets. A cross between a male with TXA2+ platelets (presumed genotype tt) and a female with TXA2+ (tt) platelets yielded 9 offspring with TXA2+ (tt) platelets and 0 with TXA2- platelets. Crossing a male presumed homozygous (TT) for TXA2- platelets with a female with TXA2+ (tt) platelets produced 2 pups with TXA2- (Tt) platelets and 0 pups with TXA2+ (tt) platelets. The same female with TXA2+ platelets crossed with a male presumed to be heterozygous (Tt) for TXA2- platelets yielded 2 pups with TXA2+ (tt) platelets and 3 pups with TXA2- (Tt) platelets. Segregation analysis of these data supports the hypothesis that the ability of dog platelets to aggregate and secrete in response to TXA2 is inherited as an autosomal recessive trait.

Temperature-sensitive tyrosinase associated with peripheral pigmentation in oculocutaneous albinism

Several types of autosomal recessive oculocutaneous albinism (OCA) are associated with abnormal tyrosinase function and a generalized reduction in or absence of cutaneous and eye melanin. Each is thought to result from a different mutant allele at the tyrosinase locus, with the mutation producing an enzyme with little or no activity in all involved tissues. In this paper, we report a new type of OCA that results from a tyrosinase allele producing a temperature-sensitive enzyme. The proband had white hair in the warmer areas (scalp and axilla) and progressively darker hair in the cooler areas (extremities) of her body. Melanocyte and melanosome architecture were normal. Quantitative hairbulb tyrosinase (dopa oxidase) assay demonstrated a loss of activity above 35-37 degrees C. Plasma pheomelanin and urine eumelanin intermediates were reduced and correlated with hair melanin content. This is the first temperature-sensitive tyrosinase mutation to be reported in humans and is analogous to the Siamese mutation in the cat and the Himalayan mutation in the mouse.

A tyrosinase gene missense mutation in temperature-sensitive type I oculocutaneous albinism. A human homologue to the Siamese cat and the Himalayan mouse

Type I oculocutaneous albinism (OCA) is an autosomal recessive disorder in which deficient synthesis of melanin pigment results from abnormal activity of melanocyte tyrosinase. A novel type I OCA phenotype in which hypopigmentation is related to local body temperature is associated with a missense substitution in tyrosinase, codon 422 CGG (Arg)----CAG (Gln). This substitution results in a tyrosinase polypeptide that is temperature-sensitive. This form of type I OCA thus is homologous to the temperature-related forms of albinism seen in the Siamese cat and the Himalayan mouse.

Emergence of self-destructive phenomena in children and adolescents during fluoxetine treatment

Self-injurious ideation or behavior appeared de novo or intensified during fluoxetine treatment of obsessive-compulsive disorder in six patients, age 10 to 17 years old, who were among 42 young patients receiving fluoxetine for obsessive-compulsive disorder at a university clinical research center. These symptoms required the hospitalization of four patients. Before receiving fluoxetine, four patients had major risk factors for self-destructive behavior including depression or prior suicidal ideation or self-injury. Three hypotheses concerning the apparent association between fluoxetine and these self-injurious phenomena are discussed: (1) coincidence; (2) disorganization of vulnerable individuals secondary to drug-induced activation; and (3) a specific serotonergic-mediated effect on the regulation of aggression.

Non-random distribution of missense mutations within the human tyrosinase gene in type I (tyrosinase-related) oculocutaneous albinism

Type I oculocutaneous albinism (OCA) is produced by mutations of the tyrosinase gene. We report four new missense mutations in the tyrosinase gene in patients with type IA OCA. Three of these mutations occur within exon I and the fourth mutation within exon IV. Analysis of the distribution of these four missense mutations and 12 previously reported missense mutations shows that most cluster in four areas of the gene. Two clusters involve the copper A and copper B binding sites and could disrupt the metal ion-protein interaction necessary for enzyme function. The other two clusters are in exon I and exon IV and could represent important functional domains of the enzyme. We conclude that analysis of the tyrosinase missense mutations will provide insight into the structure-function relationship of this enzyme.

Sudden death in children receiving Norpramin: a review of three reported cases and commentary

The 1990 "package insert" for Norpramin, the Merrell Dow Pharmaceuticals Inc., brand of desipramine, was changed to include the following statement in the Adverse Reactions section, "There has been a report of an 'acute collapse' and 'sudden death' in an eight-year-old (18 kg) male, treated for two years for hyperactivity. There have been additional reports of sudden death in children." The purpose of this commentary is to review what is known about the three reported cases of sudden death and to discuss the implications of these tragedies for children receiving treatment with tricyclic drugs.

Visual anomalies associated with albinism

All mammals with hypopigmentation of the retinal pigment epithelium have abnormal visual systems. Albino mammals have been found to have: (1) reduced numbers of uncrossed optic fibers projecting to all visual centers, (2) disorganization of the pattern (lamination) of the dorsal lateral geniculate nuclei, and (3) disorganization of projections from the dorsal lateral geniculate nuclei to the visual cortex. The disorganization of central visual centers has catastrophic effects on stereovision and optokinetic nystagmus. Variable expression in oculocutaneous albinism suggests that affected individuals cannot always be identified by hypopigmentation, reduced visual acuity and nystagmus. Careful observation of foveal development in individuals even with normal vision is necessary to detect all persons with albinism. The scalp-recorded visually evoked potential designed to detect optic misrouting is the most reliable concomitant for determining albinism.

Albinism and Hermansky-Pudlak syndrome in Puerto Rico

Five types of oculocutaneous albinism and two types of ocular albinism were found among 349 Puerto Rican albinos. The most prevalent type of albinism was the Hermansky-Pudlak syndrome (HPS). HPS was observed in five of every six albinos in Puerto Rico. The prevalence of HPS was highest in the northwestern quarter of the island, affecting approximately one in 1,800 persons, and approximately one in 22 are carriers of the gene. HPS is an autosomal recessively inherited triad of a tyrosinase-positive type of albinism, a hemorrhagic diathesis due to storage pool deficient platelets and accumulation of ceroid in tissues. The pigmentary phenotype of HPS albinos resembled that of any other type of oculocutaneous or ocular albinism. The most reliable method of diagnosing HPS is by a deficiency of platelet dense bodies observed by electron microscopy. The accumulation of ceroid in the tissues is associated with fibrotic restrictive lung disease and granulomatous enteropathic disease. The enteropathic disorder resembles Crohn's disease and with few exceptions, had its onset after 13 years of age. The major causes of death were fibrotic restrictive pulmonary disease, hemorrhagic episodes and sequelae of granulomatous enteropathic disease. Menometrorrhagia was common in women with HPS. No immune deficiency was found in HPS patients. The majority of patients with HPS had visual acuities of 20/200 or worse and consequently were legally blind. Albinos of all types, including HPS, lacked binocular vision due to nearly complete crossing of the optic tracts.

A frequent tyrosinase gene mutation in classic, tyrosinase-negative (type IA) oculocutaneous albinism

We have identified a tyrosinase gene mutation in several patients with classic, tyrosinase-negative (type IA) oculocutaneous albinism. This mutation, which results in a proline----leucine substitution at codon 81 of the tyrosinase polypeptide (EC 1.14.18.1), was observed in 20% (6 of 30) of oculocutaneous albinism alleles from independent probands, but it was not observed in any normal individuals. This mutation thus appears to be a frequent cause of tyrosinase-negative oculocutaneous albinism.

Role of supraspinal systems in environmentally induced antinociception: effect of spinalization and decerebration on brief shock-induced and long shock-induced antinociception

Prior research suggests that afferent nociceptive information can directly activate the opioid and nonopioid brainstem antinociceptive systems. Grau (1987a) has hypothesized that direct activation occurs when an organism is exposed to severe aversive stimuli and that forebrain systems mediate the activation of the antinociception systems when mild aversive stimuli are used. The present experiments tested this hypothesis by examining the impact of spinalization and decerebration on the antinociception observed after mild (3 0.75-s 1.0-mA shocks) and vs. severe (3 25-s 1.0-mA shocks) tailshocks. It was found that spinal transection eliminated the antinociception observed after both shock schedules, whereas decerebration blocked mild shock-induced, but not severe shock-induced, antinociception. Surprisingly, decerebration potentiated severe shock-induced antinociception. The opioid antagonist naltrexone had no effect on the antinociception observed after severe shock in sham or decerebrate rats.

Role of supraspinal systems in environmentally induced antinociception: Effect of spinalization and decerebration on brief shock-induced and long shock-induced antinociception

Prior research suggests that afferent nociceptive information can directly activate the opioid and nonopioid brainstem antinociceptive systems. Grau (1987a) has hypothesized that direct activation occurs when an organism is exposed to severe aversive stimuli and that forebrain systems mediate the activation of the antinociception systems when mild aversive stimuli are used. The present experiments tested this hypothesis by examining the impact of spinalization and decerebration on the antinociception observed after mild (3 0.75-s 1.0-mA shocks) and vs. severe (3 25-s 1.0-mA shocks) tailshocks. It was found that spinal transection eliminated the antinociception observed after both shock schedules, whereas decerebration blocked mild shock-induced, but not severe shock-induced, antinociception. Surprisingly, decerebration potentiated severe shock-induced antinociception. The opioid antagonist naltrexone had no effect on the antinociception observed after severe shock in sham or decerebrate rats.

Frontal cortex lesions block the opioid and nonopioid hypoalgesia elicited by brief shocks but not the nonopioid hypoalgesia elicited by long shocks

Previous research (Grau, 1987a, 1987b) suggests that forebrain systems play an essential role in the hypoalgesia observed after brief shock but not long shock. Additional research has shown that pentobarbital anesthesia and decerebration block the hypoalgesia observed after 3 brief (0.75-s) shocks but not the hypoalgesia observed after 3 long (25-s) shocks. This is a study of whether a specific forebrain lesion, a frontal cortex lesion, would have a similar impact on hypoalgesia induced by brief (0.75 s) and long (25-s) shocks. Frontal cortex lesions, like decerebration and pentobarbital anesthesia, eliminated the hypoalgesia observed after brief but not long shocks. Because other research suggests that the stress of surgery may influence whether the hypoalgesia elicited by shock is opioid or nonopioid, the 2nd experiment was to examine whether the sham operation per se alters the form of the hypoalgesia observed after brief shock. It does not; in the sham-treated subjects, brief shock induced the usual transient nonopioid hypoalgesia followed by prolonged opioid hypoalgesia. These data suggest that frontal cortex lesions block nonopioid and opioid hypoalgesia observed after brief shock.

Genetic linkage analysis of hereditary arthro-ophthalmopathy (Stickler syndrome) and the type II procollagen gene

Hereditary arthro-ophthalmopathy (AO), or Stickler syndrome, is a dominantly inherited disorder characterized by vitreo-retinal degeneration and frequently accompanied by epiphyseal dysplasia and premature degenerative joint disease. Three large families with AO were analyzed for clinical manifestations of the disease and for coinheritance of the genetic defect with RFLPs in the type II procollagen gene (COL2A1). Genetic linkage between AO and COL2A1 was demonstrated in the largest family, with a maximum LOD score of 3.52 at a recombination distance of zero. Data from a second family also supported linkage of AO and COL2A1, with a LOD score of 1.20 at a recombination distance of zero. These results are consistent with the conclusion that mutations in the COL2A1 gene are responsible for AO in these two families. In a third AO family, however, recombination between AO and COL2A1 occurred in at least one meiosis, and the data were inconclusive with respect to linkage.

Behavioral effects of neurotensin: operant responding and assessment of 'anhedonia'

Neurotensin and antipsychotic drugs share certain properties. This study investigates whether neurotensin and neuroleptics share the ability to produce 'anhedonia'. A dose-response curve for the effect of neurotensin on continuously reinforced behavior was obtained in Experiment 1. Centrally administered neurotensin reduced food-reinforced responding. Based on the results of Experiment 1, a dose of neurotensin (0.95 micrograms) was chosen which had minimal effects on food-reinforced operant responding. To test for anhedonia, repeated presentations of this dose were given. Because response rates did not decrease over repeated testing, no evidence for anhedonia was found.

The role of heredity in cancer

Heredity is generally felt to play a minor role in the development of cancer. This review critically examines this assumption. Topics discussed include evidence for heritable predisposition in animals and humans; the potential importance of genetic-environmental interactions; approaches that are being used to successfully locate genes responsible for heritable predisposition; comparability of genetic findings among heritable and corresponding sporadic malignancies; and future research directions. Breast, colon, and lung cancer are used to exemplify clinical and research activity in familial cancer; clinical phenotypes, segregation and linkage analyses, models for environmental interactions with inherited traits, and molecular mechanisms of tumor development are discussed. We conclude that the contribution of heredity to the cancer burden is greater than generally accepted, and that study of heritable predisposition will continue to reveal carcinogenic mechanisms important to the development of all cancers.

Frontal cortex lesions block the opioid and nonopioid hypoalgesia elicited by brief shocks but not the nonopioid hypoalgesia elicited by long shocks

Previous research (Grau, 1987a, 1987b) suggests that forebrain systems play an essential role in the hypoalgesia observed after brief shock but not long shock. Additional research has shown that pentobarbital anesthesia and decerebration block the hypoalgesia observed after 3 brief (0.75-s) shocks but not the hypoalgesia observed after 3 long (25-s) shocks. This is a study of whether a specific forebrain lesion, a frontal cortex lesion, would have a similar impact on hypoalgesia induced by brief (0.75 s) and long (25-s) shocks. Frontal cortex lesions, like decerebration and pentobarbital anesthesia, eliminated the hypoalgesia observed after brief but not long shocks. Because other research suggests that the stress of surgery may influence whether the hypoalgesia elicited by shock is opioid or nonopioid, the 2nd experiment was to examine whether the sham operation per se alters the form of the hypoalgesia observed after brief shock. It does not; in the sham-treated subjects, brief shock induced the usual transient nonopioid hypoalgesia followed by prolonged opioid hypoalgesia. These data suggest that frontal cortex lesions block nonopioid and opioid hypoalgesia observed after brief shock.

One versus two simultaneous goniotomies as the initial surgical procedure for primary infantile glaucoma

To evaluate whether a more extensive incision of the tissue adjacent to the anterior trabecular meshwork resulted in more effective control of intraocular pressure (IOP), seven infants with bilateral congenital glaucoma underwent a single goniotomy in one eye and two simultaneous goniotomies at separate sites in the second. Sodium hyaluronate (Healon) was used in all eyes undergoing two simultaneous goniotomies and in three to seven eyes undergoing a single goniotomy. Success was not significantly different, at 1 month or 1 year postoperatively, for eyes which underwent two simultaneous and separate goniotomies. Successful control of IOP was, however, related to the preoperative IOP. Eyes for which the initial procedure was unsuccessful had a significantly higher IOP. The incidence of postoperative hyphemas was less in eyes in which the Healon was used intraoperatively, but the use of Healon did not favorably or adversely affect intraocular pressure control.

Identification of carriers of Duchenne muscular dystrophy: value of molecular analysis

Currently, molecular methods are the most accurate diagnostic tools for carrier detection and prenatal diagnosis of Duchenne muscular dystrophy (DMD). This report illustrates the value of molecular diagnosis as opposed to previous diagnostic methods, the need for frequent re-evaluations as new methodologies develop, and the necessity for in-depth genetic counseling. In Family 1, the proposita was predicted to be a carrier by an indirect assay (abnormal in vitro muscle ribosomal protein synthesis). DNA analysis using restriction fragment length polymorphisms (RFLPs) indicated that she was not a carrier. She gave birth to a predicted non-affected male, who inherited the gene in question. In Family 2 the proposita, an obligate carrier, was initially evaluated by RFLP analysis. Two pregnancies were monitored by first trimester chorionic villous sampling. Re-evaluation indicated that all affected individuals, including one of the embryos, carried a deletion of the dystrophin gene. The identification of an RFLP within the region containing the deletion allowed unambiguous determination of the carrier status of all individuals.

Effect of growth hormone on growth and myelination in the neonatal hypothyroid rat

The possible involvement of a deficit of GH and insulin-like growth factor-I (somatomedin C) (IGF-I/SMC) in mediating the effects of propylthiouracil (PTU)-induced hypothyroidism on body and skeletal growth and myelination was studied in the neonatal rat. Myelination (as assessed by 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) activity), skeletal growth (as assessed by tail length) and body weight of pups from PTU-treated mothers were significantly retarded compared with normal animals or euthyroid controls. At 20 days after birth, plasma GH in hypothyroid animals was undetectable (less than 10 micrograms/l), pituitary GH content was 1.2% of control, and plasma, liver and kidney IGF-I/SMC concentrations were 63, 68 and 50% of control values respectively. CNP activity in hypothyroid brain was 52% of normal controls but the concentration of IGF-I/SMC was 113-154% of control. Treatment of hypothyroid animals from day 1 with GH (10 mg/kg body weight per day) restored liver and plasma IGF-I/SMC concentrations at 20 days to values above those of normal animals and euthyroid controls. The concentration of IGF-I/SMC was also significantly (P less than 0.001) restored in hypothyroid kidney (79% of normal), but the concentration in brain was unaffected. These observations provide evidence that the GH treatment employed in the present experiments was adequate to restore the deficit. GH treatment had no significant effect on tail length or CNP activity, and only a small (4-24%) effect on body weight at 20 days. Only thyroxine was able fully to restore body weight and substantially restore tail length and CNP activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Function of dopachrome oxidoreductase and metal ions in dopachrome conversion in the eumelanin pathway

The conversion of dopachrome (DC) in the eumelanin pathway has been analyzed to determine the specific product and the role of enzyme control. 5,6-Dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) were quantitated by HPLC with fluorescent detection, after DC incubation with heated and unheated preparations of B-16 melanoma derived dopachrome oxidoreductase (DCOR). The enzyme-catalyzed reaction produced DHICA as the major product, while DHI formed with the spontaneous reaction. It had originally been suggested that the major product of DC conversion was DHI, with DHICA being formed as a minor product of this conversion [Raper, H.S. (1927) Biochem. J. 21, 89-96]. Copper, nickel, and cobalt ions promoted conversion of DC, with nickel simulating DCOR activity. Removal of free ions from unheated DCOR did not alter DC conversion. We conclude that the major product of DC conversion is DHICA and that DCOR is responsible for this conversion.

Correcting image distortion with fiber-optic tapers

We examine an ultraviolet camera used aboard a rotating spacecraft where the image motion due to spacecraft spin is canceled by synchronously stepping the image charge accumulating in a charge coupled detector. Critical to this procedure is the flattening of a velocity field associated with the spherical focal surface of the Burch configuration camera. We show that this can be efficiently accomplished by a tapered fiber-optic bundle having one surface figured to a cylinder whose axis lies along the charge-stepping direction.

Albinism

Genetic abnormalities of the melanin pigment system in which the synthesis of melanin is reduced or absent are called albinism. The reduction in melanin synthesis can involve the skin, hair follicle, and eye, resulting in oculocutaneous albinism, or can be localized primarily to the eye, resulting in ocular albinism. Approximately 1 in 17,000 individuals in the United States has oculocutaneous albinism, and more than 1 per cent of the population are heterozygous for a gene producing albinism.

Hermansky-Pudlak syndrome. Ophthalmic findings

Prospective ophthalmic evaluation was performed in 20 individuals with Hermansky-Pudlak syndrome, a type of oculocutaneous albinism with an associated deficiency of dense bodies in platelets. The extent of visual impairment and the possible relationship to the degree of hypopigmentation were studied. All patients showed nystagmus, visual acuity ranged from 20/60 to 20/400, and correction of refractive error provided a mild improvement in vision. Iris pigmentation varied in amount and did not correlate with the visual acuity measurement. Foveal hypoplasia was found in all patients, but variability in macular transparency and vascular architecture was noted. Visual-evoked potentials performed in 11 patients demonstrated excessive decussation of optic fibers. Recognition of this form of oculocutaneous albinism is important because of the associated pulmonary, gastrointestinal, renal, and cardiac manifestations of Hermansky-Pudlak syndrome.

Effects of opioid microinjections into the medial septal area on spatial memory in rats

Recent work has demonstrated that posttraining systemic opioid antagonist administration facilitates the acquisition of a radial arm maze task in new spatial environments. In this study, we examined the effect of posttraining naloxone and beta-endorphin microinjections into the medial septal area on the acquisition of a radial maze task in new spatial environments. The results of these experiments demonstrated that posttraining intraseptal naloxone administration facilitated, whereas posttraining intraseptal beta-endorphin administration impaired, the acquisition of criterion performance on a maze task performed in new spatial environments. Further, intraventricular beta-endorphin administration did not produce effects that were comparable to those observed following intraseptal beta-endorphin administration, which indicates that the septal region is a brain site that is sensitive to the effects of opioids on spatial memory in new environments. Further, posttraining intraseptal beta-endorphin administration had no effect on working memory in a familiar spatial environment, whereas pretraining intraseptal beta-endorphin administration had no effect on the performance of a previously acquired spatial task.

Reoperations for esotropia

The results of bilateral medial rectus rerecession and bilateral lateral rectus resection for patients with undercorrected or recurrent esotropia after medial rectus recession are compared. Medial rectus rerecession resulted in a high rate of consecutive exotropia. Lateral rectus resection was more accurate but was often accompanied by undercorrection. Minimal millimeter amounts of rerecession yielded large diopter results. Except in cases where medial restrictive factors or obvious errors in magnitude of the original surgery are noted, we feel that bilateral lateral rectus resection is the surgery of choice in patients with recurrent or undercorrected esotropia following medial rectus recession.

Hypopigmentation in the Prader-Willi syndrome

Cutaneous and ocular pigmentation were evaluated in 29 individuals with the Prader-Willi syndrome (PWS). Criteria for hypopigmentation included the presence of type I or II skin, the lightest skin type in the family by history, and iris translucency on globe transillumination. On the basis of these criteria, 48% of the PWS individuals were hypopigmented. The presence of hypopigmentation correlated with a small interstitial deletion on the proximal long arm of chromosome 15; however, this deletion was also found in individuals who did not meet the full criteria for hypopigmentation. Hairbulb tyrosinase activity and glutathione content, as well as urine cysteinyldopa excretion, were low in PWS individuals with and without hypopigmentation and did not separate these two groups. We conclude that hypopigmentation is found in a significant proportion of individuals with PWS and that the hypopigmentation may be associated with a deletion of the long arm of chromosome 15. The mechanism for the hypopigmentation is unknown.