Isolation of the major subcellular organelles from mouse liver using Nycodenz gradients without the use of an ultracentrifuge

Commonly, subcellular organelles such as nuclei, mitochondria, lysosomes, and Golgi membranes are isolated first by differential centrifugation in low-speed or high-speed centrifuges and then purified by gradient centrifugation in ultracentrifuges. We have prepared these organelles using a new high-speed centrifuge (28,000 rpm max) which allows the generation of higher radial centrifugal forces (rcfs) than are available in standard machines. We have shown that most subcellular organelles can be purified by using low-viscosity Nycodenz gradients at rcfs lower than those normally used in ultracentrifuges, without increasing the time of centrifugation. Use of Nycodenz also allows rapid harvesting of material from gradients and we have adapted a number of enzyme assays to facilitate gradient analysis.

Atelosteogenesis type III: a distinct skeletal dysplasia with features overlapping atelosteogenesis and oto-palato-digital syndrome type II

We present 5 cases of a short-limb dwarfism syndrome whose manifestations overlap those of atelosteogenesis and oto-palato-digital syndrome Type II. Clinical, radiographic, genetic, and histologic data are presented which demonstrate differences between our patients and previously reported cases of these other conditions. We conclude that the disorder seen in these children represents a distinct chondrodysplasia for which we propose the name atelosteogenesis Type III.

Chlamydial infections

Chlamydia causes many human infections and should be treated aggressively. Tetracycline or doxycycline are the drugs of choice, but erythromycin can be used if a drug allergy is present or if tetracyclines are contraindicated. In the pregnant woman, aggressive treatment can improve neonatal outcome. In the United States, each year 155,000 infants are exposed to Chlamydia trachomatis during the birth process, and more than 100,000 will be infected. Of these, 75,000 will get conjunctivitis, and 30,000 will get pneumonia. In pregnancy, erythromycin is the drug of choice, with treatment recommended after initial culture and at term if repeat cultures are positive. If erythromycin is not tolerated, or the patient has an allergy to it, ampicillin or clindamycin may be effective alternatives.

Osteogenesis imperfecta. The position of substitution for glycine by cysteine in the triple helical domain of the pro alpha 1(I) chains of type I collagen determines the clinical phenotype

Skin fibroblasts grown from three individuals with osteogenesis imperfecta (OI) each synthesized a population of normal type I collagen molecules and additional molecules that had one or two alpha 1(I) chains that contained a cysteine residue within the triple-helical domain, a region from which cysteine normally is excluded. The patients had very different phenotypes. One patient with OI type I had a population of alpha 1(I) chains in which glycine at position 94 of the triple helix was substituted by cysteine; a patient with OI type III had a population of alpha 1(I) chains in which glycine at position 526 of the triple helix was substituted by cysteine; and the third patient, with OI type II, had a cysteine for glycine substitution at position 718 of the alpha 1(I) chain. From all three patients, molecules that contained two mutant chains formed interchain, intramolecular disulfide bonds, and although less stable to thermal denaturation than normal molecules, they were more stable than molecules that contained only a single mutant chain. These findings indicate that substitutions for glycine within the triple-helical domain of the alpha 1(I) chain are not invariably lethal and that their phenotypic effect largely depends on the nature of the substituting residue and its location in the chain.

Case report and delineation of the congenital hypothalamic hamartoblastoma syndrome (Pallister-Hall syndrome)

We report one new case of congenital hypothalamic hamartoblastoma syndrome (Pallister-Hall syndrome) and one case of a diencephalic nodule associated with craniofacial malformations. Based on a review of 11 cases of Pallister-Hall syndrome documented by pathological examination, two cases presumed by phenotype, three cases of hypothalamic hamartoma with craniofacial anomalies only, and several cases of related interest, we delineate the clinical, neuroradiologic, and neuropathologic manifestations which aid in differential diagnosis. Clinical manifestations in infants with Pallister-Hall syndrome included postaxial polydactyly with nail dysplasia, short nose with flat nasal bridge, apparently low-set, posteriorly angulated ears, kidney and lung anomalies, congenital heart defects, imperforate anus, and micropenis with undescended or hypoplastic testes in males. These manifestations were associated with varying degrees of panhypopituitarism and pituitary aplasia. In three cases of hypothalamic hamartoma associated with craniofacial anomalies only, the face resembled that of holoprosencephaly. Other cases of hypothalamic hamartoma have had associated palate or heart defects or presented with precocious puberty. Of the infants with a hypothalamic hamartoblastoma at autopsy, neuropathologic findings were consistent with a primitive neuroectodermal tumor. Surgical tissue from our sole survivor suggested such tumors might mature, and the tumor has not recurred. Neuroradiologic diagnosis may be difficult but should be attempted in infants with these clinical manifestations; due to the need for prompt initiation of appropriate therapy.

Triploidy: pregnancy complications and clinical findings in seven cases

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth-Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.

Development of coronary prevention strategies by health authorities in the United Kingdom

The United Kingdom has one of the highest coronary heart disease mortality rates in the world. However, over the last decade there has been a growing impetus in coronary prevention. In 1988 the Faculty of Community Medicine carried out a survey of all health authorities in the UK to assess the progress and problems with coronary prevention. This survey received a 92 per cent response rate and shows some interesting findings. The picture at present reveals a growing momentum in the last couple of years with half the health authorities at present claiming to have a programme. The main hindrances reported are lack of funding rather than lack of interest. The development and difficulties with nutrition and smoking policies, and with blood pressure screening are also described. The regional pattern of development of these programmes and policies is complex. Many authorities favour a general health promotion approach rather than a negative, disease oriented one; this conflict in approach requires further debate.

Quantitative calibration and use of DNA probes for investigating chromosome abnormalities in the Prader-Willi syndrome

Ten genomic DNA probes, subcloned from inserts derived from a phage library constructed from the DNA of flow-sorted chromosomes, have now been mapped to locations within 15q11-15q13. By dosage blotting and densitometry, 5 of these probes map to the 15q11.2-15q12 segment missing in one 15 chromosome of a Prader-Willi syndrome (PWS) patient with a prominent cytological deletion. A sixth probe most likely maps to the same region. The other 4 probes map outside of this segment but within 15q11-15q13. Several of the 15q11.2-15q12 probes, and a cDNA probe homologous to one, have been used to test the DNA from 8 patients exhibiting a wide range of the clinical manifestations expected for PWS patients. DNA deletion was observed in all 3 patients with cytological 15q1 deletions as well as in a patient with an unbalanced (Y;15) translocation. DNA from 1 PWS patient with an unbalanced (5;15) translocation and an inverted duplication of the short arm and proximal long arm of 15 showed at least 1 and possibly 2 extra copies of each genomic probe tested. In the other 3 patients with no cytological deletions, no DNA deletions were found. Thus, the molecular probes described can be used in most PWS patients to analyze the region of proximal 15q implicated in this syndrome.

Restriction fragment length polymorphisms within proximal 15q and their use in molecular cytogenetics and the Prader-Willi syndrome

Restriction fragment length polymorphisms (RFLPs) are described in detail for 6 DNA probes (D15S9-13, D15S18) that localize to the proximal long arm of human chromosome 15 (15q11-15q13: this report and Tantravahi et al., Am. J. Med. Genet. 33:78-87. Multiple RFLPs are detected by the probe that identifies locus D15S13, and these RFLPs are shown by genomic mapping to result from a nearby insertion or deletion of 1.8 kilobases (kb) of DNA. This set of RFLPs detected by proximal 15q probes can be used for studies on the Prader-Willi syndrome (PWS) and on mentally retarded individuals with a supernumerary inv dup(15) chromosome. Five of the polymorphic loci (D15S9-13) map to the region implicated in the cause of the PWS (15q11.2-15q12). Each of 4 families tested with these probes, as well as an additional "PWS-like" patient, was informative by RFLP analysis. The two PWS deletions studied, which occurred de novo, were inherited from the chromosome 15 provided by the father. By contrast, the 2 inv dup(15) chromosomes analyzed were of maternal origin. The use of RFLPs can also simplify the molecular determination of copy number in chromosomal aneuploidy, as exemplified by analysis of individuals with the PWS and a deletion, patients with an inv dup(15), and one patient with a more complex rearrangement involving chromosome 15. Our studies demonstrate the application of DNA probes for both molecular cytogenetic studies on this chromosome region and the development of diagnostic molecular markers to aid early clinical diagnosis of the PWS.

Acrocallosal syndrome: new findings

We describe a 21-month-old girl with typical manifestations of the acrocallosal syndrome of craniofacial anomalies, agenesis of the corpus callosum, hallucal duplication, severe hypotonia, and psychomotor retardation. Our patient also had the Dandy-Walker malformation, imperforate anus with rectovaginal fistula, hypothalamic dysfunction with hypothyroidism and diabetes insipidus, thick, dysplastic pulmonic valve leaflets, central and obstructive apnea, and pulmonary hypertension. These findings add to the delineation of this syndrome.

Angelman and Prader-Willi syndromes share a common chromosome 15 deletion but differ in parental origin of the deletion

Many Prader-Willi syndrome (PWS) and Angelman syndrome (AS) patients have a cytogenetic deletion of 15q11q13. While AS and PWS share a similar cytogenetic anomaly, they have very different clinical phenotypes. DNAs from 4 AS patients were examined using 5 chromosome 15q11q13-specific cloned DNA segments. With the present level of resolution, the molecular deletions between AS and those previously reported for PWS did not appear to differ. However, in contrast to the paternal inheritance of the deleted chromosome 15 observed in the majority of PWS patients, maternal inheritance of the deleted chromosome 15 was demonstrated in the AS patients by restriction fragment length polymorphisms (RFLPs).

Ion modulation of membrane permeability: effect of cations on intact cells and on cells and phospholipid bilayers treated with pore-forming agents

Leakage of ions (Na+, K+) and phosphorylated metabolites (phosphorylcholine, 2-deoxyglucose 6-phosphate) through membrane lesions in intact cells or in cells modified by 'pore-forming' agent has been studied. Leakage from intact cells is induced by protons and by divalent cations such as Cu2+, Cd2+ or Zn2+. Leakage from agent-modified cells--or across phospholipid bilayers modified by agent--is prevented by low concentrations of the same cations and by higher concentrations of Ca2+, Mn2+ or Ba2+; Mg2+, dimethonium, spermine, or spermidine are virtually ineffective. The relative efficacy of a particular cation (e.g. Ca2+) depends more on cell type than on the nature of the pore-forming agent. The predominant effect is on binding of cation to specific sites, not on surface charge. Surface charge, on the other hand, does affect leakage from agent-modified cells in that suspension in nonionic media reduces leakage, which can be restored by increasing the ionic strength: univalent (Na+, K+, Rb+, NH4+) and divalent (Mg2+, dimethonium) cations are equally effective; addition of protons or divalent cations such as Zn2+ to this system inhibits leakage. From this and other evidence here presented it is concluded that leakage across membranes is modulated by the presence of endogenous anionic components: when these are in the ionized state, leakage is favored; when unionized (as a result of protonation) or chelated (by binding to divalent cation), leakage is prevented. It is suggested that such groups are exposed at the extracellular face of the plasma membrane.

Rett syndrome: natural history and management

The clinical findings of seven girls and one woman, 2 to 25 years of age, with Rett syndrome are presented. Previous diagnoses included Prader-Willi syndrome, Angleman syndrome, toxic reaction to pertussis vaccine, CNS dysgenesis, and encephalitis. Rett syndrome has a recognizable neurodevelopmental phenotype without a specific biologic marker, which makes the diagnosis difficult at times. Treatment is largely supportive, and an active parents' association has been helpful to many families.

Spontaneous dissection of the common carotid artery. Case report and review of the literature

Spontaneous dissection of the internal carotid artery is not a rare occurrence. However, spontaneous dissection of the common carotid artery has not been recognized and the first reported case and its management are described.

Oral and written language abilities of XXY boys: implications for anticipatory guidance

Previous studies of XXY boys suggest that they are at risk for certain communication disorders involving oral and written language. In this study, the language, reading, and spelling skills of a group of 14 XXY boys identified during neonatal cytogenetic screening were compared with those of a group of 15 control children. The two groups were matched for age, grade, race, parity, birth weight, parental age and education, and socioeconomic status. The mean age of the XXY group was 9 years 7 months and that of the control group was 9 years 3 months. The mean academic grade level for both groups was at the transition between third and fourth grade. There was selective reduction in verbal IQ scores for the XXY group and no significant differences apparent between groups for performance IQ scores. The decrease in verbal IQ was associated with a reduced full-scale IQ and also with significant problems in expressive language, auditory processing abilities, and auditory memory. Word-finding difficulties and problems in the production of syntax were major components of the specific expressive language deficit. Except for difficulties in the understanding of complex sentence structures, the receptive language skills of XXY boys did not differ significantly from those of the control group. These reductions in speech and language abilities correlated with decreased achievement by the XXY group on a variety of reading and spelling tasks. These results suggest that difficulty learning how to read and spell may be due to a preexistent language disability. Early attention to such expressive language problems may be essential to ameliorate secondary maladaptive behaviors due to chronic language-related learning disabilities.

Independent dysmorphology evaluations at birth and 4 years of age for children exposed to varying amounts of alcohol in utero

Two groups of 4-year-old children were examined by a dysmorphologist without knowledge of previous examination results or prenatal exposure and categorized as to whether or not they showed fetal alcohol effects. A priori classification of children into the two groups was on the basis of their mothers' self-report of drinking when interviewed during pregnancy. Children born to 108 mothers in a "heavier" drinking group (absolute alcohol concentration greater than or equal to 30 mL/d [1.0 oz/d]) were compared with a matched group of children born to 97 mothers whose average absolute alcohol concentration was less than 0.3 mL/d (0.01 oz/d). The percentage of children with fetal alcohol effects in the heavier drinking v the comparison group was 20.4% v 9.3%. When fetal alcohol effects were studied in relation to only the absolute alcohol concentration scores, there was a significantly greater chance of a child being classified as having fetal alcohol effects with increasing levels of alcohol exposure prior to recognition of pregnancy (P = .013). A logistic regression, run on the absolute alcohol concentration scores and other primary exposures, indicated that fetal alcohol effects classification was not significantly related to nicotine, caffeine, or marijuana but was significantly related to absolute alcohol concentration scores even after statistically adjusting for these other exposures (P = .002). Classification of fetal alcohol effects at 4 years of age was compared to a fetal alcohol effects classification obtained at birth by an independent dysmorphologist in a sample of 75 subjects examined at both ages, and 80% of the infants classified as having fetal alcohol effects at birth were classified as having fetal alcohol effects at 4 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Ring chromosome 12

A ring chromosome 12 (p13.3q24.3) was observed in all cells analyzed from skin fibroblasts and the peripheral blood of a 19-year-old man initially referred for developmental delay with expressive language deficiency. Other phenotypic anomalies included growth deficiency, multiple café-au-lait spots, mild pectus excavatum, glandular hypospadias, left esotropia, clinodactyly of the fifth fingers, and hypothyroidism with elevated antithyroid antibodies. The four previously reported cases of r(12) support the theory of a general ring phenotype which is manifested independently of the specific autosome involved and which is characterized by growth failure, moderate mental retardation, and lack of other major phenotypic anomalies. Breakpoints in all cases of r(12) have been assigned to the telomeric regions, suggesting minimal deletion of chromosome material.

A de novo interstitial deletion of chromosome 6 (q22.2q23.1)

A unique interstitial deletion of the long arm of chromosome 6 involving bands q22.2 and q23.1 was observed in a patient referred for craniostenosis and developmental delay. The associated phenotypic anomalies are compared with other reported cases of deletion 6q involving adjacent regions.

Free proximal trisomy 21 without the Down syndrome

Analysis of partial duplication of chromosome 21 suggests that band 21q22 contains determinants for the Down syndrome. We report two cases of free proximal trisomy 21 without manifestations of the Down syndrome. Phenotypic anomalies included marked microcephaly, short stature, hypoplastic nails, and mental retardation/developmental delay. Our cases are consistent with the assignment of band 21q22 as the causal duplicated segment in the Down syndrome.

Prenatal diagnosis of a new syndrome: holoprosencephaly with hypokinesia

Markedly decreased fetal activity (akinesia/hypokinesia) is usually readily apparent to experienced mothers, and frequently this concern leads to attempts at prenatal diagnosis. We report prenatal diagnosis of two fetuses with congenital contractures, markedly decreased fetal movement, and microcephaly due to severe holoprosencephaly. Such familial recurrence to phenotypically normal parents suggests a newly recognized autosomal recessive or X-linked syndrome that is readily detectable by prenatal ultrasonography.

Bilateral renal agenesis in three consecutive siblings

We report here an unusual recurrence of bilateral renal agenesis (BRA) in three consecutive siblings. Chromosome analysis was normal, as were renal ultrasound studies on both parents and their surviving child. Ultrasound was employed prenatally to diagnose Potter's syndrome in both of the recurrences, and autopsy confirmed BRA in otherwise normal fetuses. Recurrence of BRA points to the usefulness of ultrasound in monitoring subsequent pregnancies in couples who have had one such occurrence. Ultrasound studies should also be performed in non-affected family members to detect the presence of asymptomatic anomalies of the genitourinary system, but a negative family study does not preclude recurrence of BRA.

Diminished complications in a non DR3 DR4 family with insulin-dependent diabetes

A family is reported in which the mother and both of her children developed insulin-dependent diabetes mellitus between 9 and 19 months of age, reflecting the importance of heredity in the natural history of this disease. That overt complications of diabetes were not present in any of the individuals, and that blood sugars were maintained close to normal on relatively small amounts of exogenous insulin, suggests a protective function in these patients related to residual secretion of insulin by beta cells. Human lymphocyte antigen (HLA) typing in this family showed that, although the diabetic children had identical HLA types, neither the mother nor her children possessed the diabetes-associated antigen HLA-DR3 or HLA-DR4. This raises the possibility that selective loss of diabetes-susceptible fetuses (suggested to be responsible for the low risk of diabetic mothers producing diabetic offspring) may be influenced by the HLA type of the mother.