Frataxin, iron-sulfur clusters, heme, ROS, and aging

A deficiency in mitochondrial frataxin causes an increased generation of mitochondrial reactive oxygen species (ROS), which may contribute to the cell degenerative features of Friedreich's ataxia. In this work the authors demonstrate mitochondrial iron-sulfur cluster (ISC) defects and mitochondrial heme defects, and suggest how both may contribute to increased mitochondrial ROS in lymphoblasts from human patients. Mutant cells are deficient in the ISC-requiring mitochondrial enzymes aconitase and succinate dehydrogenase, but not in the non-ISC mitochondrial enzyme citrate synthase; also, the mitochondrial iron-sulfur scaffold protein IscU2 co-immunoprecipitates with frataxin in vivo. Presumably as a consequence of the iron-sulfur cluster defect, cytochrome c heme is deficient in mutants, as well as heme-dependent Complex IV. Mitochondrial superoxide is elevated in mutants, which may be a consequence of cytochrome c deficiency. Hydrogen peroxide, glutathione peroxidase activity, and oxidized glutathione (GSSG) are each elevated in mutants, consistent with activation of the glutathione peroxidase pathway. Mutant status blunted the effects of Complex III and IV inhibitors, but not a Complex I inhibitor, on superoxide production. This suggests that heme defects late in the electron transport chain of mutants are responsible for increased mutant superoxide. The impact of ISC and heme defects on ROS production with age are discussed.     

Eighty-fourth annual session. He Hahnemann Medical College,Philiadelphia, April 19, 20, 21, 22, 1971. Officers,abstracts, demonstrations

The mature ultimobranchial follicle of the rat consists of two or more layers of cells (U cells) surrounding a lumen containing cell debris. The ultrastructure of the outer, or basal, U cell is characterized by the presence of half desmosomes on the basal plasma membrane and pinocytotic vesicles near it, by little granular reticulum but an abundance of free ribosomes, by clusters of fibrils connected to desmosomes and possibly free in the cytoplasm. The cell ages by accumulation of clusters of fibrils and it undergoes differentiation to form more apical U cells which contain fewer ribosomes and have fibrils dispersed in the cytoplasm. The apical U cell is desquamated into the lumen and ultimately becomes a carcass containing a dense matting of fibers and vacuoles containing a reticulated material resembling that in the lumen. U cells are observed associated with typical thyroid epithelium in the thyroid of the newborn rat in relatively large follicles containing colloid and desquamated cells. They also form rods of cells in the very young rat. Mixed follicles containing both U cells and typical thyroid epithelium occur at all ages.     

Mesangial fenestrations, sieving, filtration, and flow

Small tracers in the circulation enter the rat mesangium rapidly and in large amounts that indicate a sizable plasma flow into the mesangium. Entrance is effected through mesangial fenestrations with a mean width in scanning electron microscopy of 376 A, a size similar to fenestrations in peripheral glomerular capillary walls. This is considerably smaller than the mean size of 678 A found with transmission electron microscopy, but the difference is probably due largely to the anionic surface coat on endothelial cells. Measurements of asymmetric thorium dioxide particles show that smaller ones with a mean length of 315 A enter the mesangium preferentially and that larger particles with a mean length of 405 A are partially restricted, supporting the idea that the measured width in scanning electron microscopy is close to the actual width in vivo. Fluid flow into the mesangium requires fluid flow out. The appearance time and accumulation of tracers suggest the following exit paths of flow from the mesangium: through the overlying epithelium into the urinary space contributing to glomerular filtration and concentrating large tracers beneath the basement membrane in the paramesangial region, into the efferent glomerular capillaries after tracers have been filtered out by the fibrillar matrix, and through the hilus into the juxtaglomerular apparatus (quantitatively small).     

Recessive, sex-Iinked, progressive, oculocerebral degeneration

Norrie's disease is a rare condition with a recessive sex-linked mode of inheritance, blindness with progressive ocular degeneration, and mental retardation of varying severity. Deafness and epilepsy may occasionally occur.
The findings in a 42-year-old, male. mentally retarded patient suffering from Norrie's disease are reported. His family tree is noted and the differential diagnosis of this condition is discussed.     

Genetics, epigenetics, and the environment: switching, buffering, releasing

Increasing evidence suggests that the interactions between genes and environment might play a critical role in the pathogenesis of complex diseases, such as asthma, that exhibit a heritable component but do not follow Mendel's laws. Gene-environment interactions are extremely complex and not linear, such that the same genetic variants might be associated with opposite phenotypes in different environments. This is particularly evident for innate immunity genes, which operate at the interface between the immune system and the pathogen world. This article examines gene-environment interactions by using CD14 as a model and argues that the conflicting results of epidemiologic studies on CD14*C-159T result from differences in environmental conditions essential to modulate CD14 gene expression. Furthermore, on the basis of how rapidly environmental changes have affected the incidence of immune diseases, I argue that a full understanding of gene-environment interactions requires that epigenetic as well as classical genetic mechanisms be taken into account. Recent data about the effect of diet on gene methylation and the release of hidden genetic variation by impairment of heat shock protein 90-mediated buffering systems offer eloquent examples of how epigenetic mechanisms might affect gene-environment interactions.     

Hepatitis E virus: molecular virology, clinical features, diagnosis, transmission, epidemiology, and prevention

Hepatitis E virus (HEV), the sole member of the genus Hepevirus in the family of Hepeviridae, is the major cause of several outbreaks of waterborne hepatitis in tropical and subtropical countries and of sporadic cases of viral hepatitis in endemic and industrialized countries. Transmission of HEV occurs predominantly by the fecal-oral route although parenteral and perinatal routes have been implicated. The overall death rate among young adults and pregnant women is 0.5-3% and 15-20%, respectively. HEV is a small non-enveloped particle that consists of a polyadenylated single-strand RNA molecule containing three discontinuous and partially overlapping open reading frames. There are four major genotypes of HEV and a single serotype. At present, there are approximately 1,600 sequences of HEV that are already available at INSDC of both human and animal isolates. Diagnostic and molecular assays have been described for the accurate differentiation of ongoing from remote infection of HEV. Identification and characterization of swine HEV in the United States, Japan, and many other countries and their close relationship to locally characterized human HEV found in the same geographic areas prove that HEV is indeed a zoonotic virus and that domestic swine, wild deer, and boars are reservoirs of HEV in nature. A cell culture system for the propagation of the virus has been described, and a very successful phase 2 vaccine trial has been completed. This review summarizes the current knowledge on the molecular biology, clinical features, transmission, diagnosis, epidemiology, and prevention of HEV.     

Fanconi's anemia, medulloblastoma, Wilms' tumor, horseshoe kidney, and gonadal dysgenesis

An 18-month-old female infant with clinically and cytogenetically documented Fanconi's anemia was found to have two neoplasms previously unreported in this syndrome to our knowledge: a medulloblastoma and a Wilms' tumor, with the latter arising in a horseshoe kidney. An additional feature was pure gonadal dysgenesis. These unusual associations are discussed in the context of certain syndromes suggestive of an axial predisposition for neoplasia (kidneys-central nervous system and kidneys-gonads).     

Imprinting, learning, and memory

If a visually naive chick is exposed to one of a wide range of conspicuous objects, the chick may learn its characteristics. A series of biochemical studies has implicated a restricted part of the forebrain in this process of imprinting; a specific region (IMHV) has been identified which may be a site of information storage. Changes in the morphology of synapses occur in this region as a consequence of training. The left and right IMHV regions play different roles in the imprinting process. Exposure to a simple artificial object, a rotating red box, has different neural consequences from those associated with exposure to a complex object, a rotating stuffed jungle fowl, which resembles a conspecific. These differences may be related to the differences in complexity of the two training objects. Another possibility is that two neural systems are implicated in imprinting: a system that underlies a predisposition to approach objects resembling conspecifics and a learning system, of which IMHV is a crucial component, that is engaged by particular objects and that in "natural" circumstances also allows the chick to learn the characteristics of its mother.     

Morphological, biochemical, antigenic, and cytochemical relationships among Haemophilus somnus, Haemophilus agni, Haemophilus haemoglobinophilus, Histophilus ovis, and Actinobacillus seminis.

Morphology, biochemical reactions, pigmentation, antigens, and cell envelope proteins were examined in 12 strains of Haemophilus somnus, Haemophilus agni, Histophilus ovis, and Actinobacillus seminis. All of the strains except A. seminis are related and are considered as a single Haemophilus-Histophilus (HH) group. In immunodiffusion tests, HH group bacteria had at least two antigens common to all members of the group, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that they have similar cell envelope protein profiles. A quantitatively variable yellow pigment with absorption maxima of 430 to 435 nm was present in strains of H. somnus and H. agni. The HH group did not produce catalase and grew only in air containing 10% CO2. Of 10 HH group bacteria, 9 required thiamine monophosphate for growth. A. seminis was distinguished from the HH group by its lack of yellow pigment, production of catalase, growth in air, lack of a thiamine monophosphate requirement, and different cell envelope protein profile. In gel immunodiffusion tests, A. seminis antigens produced two lines of partial identity with the HH group when antiserum against H. somnus was used. Reference strains of Haemophilus influenzae, Actinobacillus lignieresii, and Haemophilus haemoglobinophilus were compared with the test strains. In immunodiffusion tests, a single antigen was found to be common to H. haemoglobinophilus, A. seminis, and the HH group. No similarities between any of the test strains and H. influenzae or A. lignieresii were noted. The close relationship of H. somnus, H. agni, and Histophilus ovis suggests that these unofficially named bacteria may belong to a single taxon.     

Nouns, verbs, objects, actions, and the animate/inanimate effect

We report an aphasic patient, Z.B.L., who showed a significant advantage for verbs compared to nouns in picture-naming tests. Within the object class, he performed better on animate things than on nonliving things in picture naming as well as in an "attribute judgement task". This pattern of performance is contrary to the central prediction of a recent proposal (Bird, Howard, & Franklin, 2000), which attributes noun-verb dissociation in aphasic patients to deficits in processing certain kinds of semantic features. This model proposes that conceptual representations of verbs have a lower proportion of sensory features than do representations of nouns; the same is proposed for inanimate versus animate items within the noun category. Noun deficits are assumed to arise due to impairment for the processing of sensory features. The model predicts that if a patient is more impaired for nouns than for verbs, he will also display more difficulty with animate than with inanimate objects. Contrary to predications derived from this theory, Z.B.L. performed better with animate than inanimate nouns.     

Hereditary hemochromatosis,iron, hepcidin,and coronary heart disease

Mounting evidence suggests that a state of sustained iron depletion may exert a primary protective action against coronary heart disease. A persistent criticism of the iron hypothesis has been that atherosclerosis may not be a prominent feature of hereditary hemochromatosis. The essence of this criticism is that iron cannot be a significant factor in atherogenesis in those unaffected by inherited iron overload unless an increase in atherosclerosis is observed in hereditary hemochromatosis. However, the emerging details of the physiology of hepcidin, the key hormone in iron recycling, suggest a resolution of the apparent paradox of an important role for iron in atherogenesis in the possible absence of increased plaque burden in most types of hereditary hemochromatosis.     

Multispot, multianalyte, immunoassay

Consideration of the basic principles of immunoassay design reveals that highly sensitive assays can, in principle, be developed using amounts of "sensor" antibody far smaller than are currently conventional in this field. Furthermore, when using such amounts, the fractional occupancy of antibody binding sites by analyte is independent of both sample volume and antibody concentration. Labelling of both the sensor-antibody and a developing antibody (designed to recognize either occupied or unoccupied sensor-antibody binding sites) permits the development of "ratiometric" immunoassays relying on measurement of the ratio of signals emitted by the two labelled antibodies. Furthermore, the sensor-antibody can be located within a "microspot" a few microns 2 in area. By labelling both sensor and developing antibodies with fluorescent labels, and scanning the microspot using a highly focussed laser beam, microspot immunoassays at least comparable in sensitivity with conventional "macroscopic" immunoassays are made possible. This in turn permits the development of immunoassay "arrays" capable in principle of measuring very large numbers of different substances within small samples (such as a drop of blood). The general principles and theory underlying these concepts are discussed, and preliminary experimental data using currently available instrumentation reported.     

Choanal stenosis,hypothelia, deafness,recurrent dacryocystitis,neck fistulas,short stature,and microcephaly: report of a case

We report on a 11-year-old girl with bilateral choanal stenosis, hypothelia, hearing loss, recurrent dacryocystitis, neck fistulas, short stature, and microcephaly. Only three individuals with choanal atresia from a consanguineous family have been reported. One of the patients also had hypoplastic nipples, hypotonia, and delay in speech development. Similar clinical features were seen in two children reported by Greenberg [1987: Am J Med Genet 28:931-934] and Wilson et al. [1998: Am J Med Genet 75:220-222]. They were prenatally exposed to methimazole because of maternal Graves disease. Neck fistulas and microcephaly noted in our patient were not previously reported as features of the syndrome or in the patients prenataly exposed to methimazole. Our patient and those reported by Qazi et al. [1982: Am J Med Genet 13:413-416] most probably have a rare syndrome characterized by this distinctive combination of symptoms. Prenatal exposure to methimazole can cause a phenocopy of the syndrome, which was probably the case in the patients reported by Greenberg and Wilson et al.     

Osteochondrodysplasia with rhizomelia, platyspondyly, callosal agenesis, thrombocytopenia, hydrocephalus, and hypertension

A female infant born at term to phenotypically normal nonconsanguinous parents had hypertension, thrombocytopenia, hydrocephalus, callosal agenesis, and nonlethal rhizomelic osteochondrodysplasia. Her osteochondrodysplasia was characterized roentgenographically by shortening and metaphyseal broadening of long bones, without bowing, and by platyspondyly, with deficient ossification of dorsal and central portions of vertebral bodies. By light microscopy, the iliac crest growth plate showed expansion of the zone of chondrocyte hypertrophy and degeneration, with faulty columnar alignment, sparse vascular ingrowth, and irregular mineralization at the zone of chondroosseous transformation. These findings appear to define a novel osteochondrodysplasia, which in association with hypertension, thrombocytopenia, hydrocephalus, and callosal agenesis may constitute a new syndrome.     

A double-blind, placebo-controlled, efficacy, safety, and pharmacokinetic study of INN 00835, a novel antidepressant peptide, in the treatment of major depression

BACKGROUND: INN 00835 is a synthetic pentapeptide with a potential for rapid onset of action as an antidepressant. Its efficacy was investigated in a pilot study in patients diagnosed with major depression. METHODS: Fifty two patients received either active drug - INN 00835 (26 patients) - or placebo (26 patients), subcutaneously at 0.2 mg/kg for 5 consecutive days. The patients were evaluated for an additional 4 weeks after treatment. Efficacy was evaluated by the following psychiatric rating scales: HAMD, MADRS, CSRS, CGI, and VAS. The effect of treatment was also evaluated by using a biochemical marker: changes in blood platelet serotonin (5HT) uptake rates in drug-treated patients compared to those in the placebo group. Plasma concentrations of INN 00835 were measured by LC/MS. RESULTS: Statistical analysis indicated a strong pharmacodynamic correlation between plasma drug concentrations at 1 h after dosing and the reduction in the severity of depression as measured by the psychiatric rating scales. A minimum effective plasma concentration (MEC) of INN 00835 was 5 ng/ml. Statistically significant differences in response to treatment (P<0.05) were found between patients with plasma concentrations above MEC and those in the placebo group, as well as between subjects with plasma concentrations above and below the MEC. The peak effect was observed after the 5-day treatment and the response to treatment persisted during the 4-week follow-up period. The change of 5HT uptake rates after treatment was significantly larger in the drug-treated group than in the placebo group. Limitations: This was a pilot study conducted in a relatively small population (52 patients) and the limited number of blood sampling times did not allow a comprehensive pharmacokinetic analysis. There was a relatively large placebo response. The results have to be confirmed in future, large scale studies. CONCLUSIONS: INN 00835 appears to be a promising drug for the treatment of major depression.     

Experimental kerma coefficients and dose distributions of C, N, O, Mg, Al, Si, Fe, Zr, A-150 plastic, Al203, AlN, SiO2 and ZrO2 for neutron energies up to 66 MeV

Low-pressure proportional counters (LPPCs) with walls made from the elements C, Mg, Al, Si, Fe and Zr and from the chemical compounds A-150 plastic, AlN, Al2O3, SiO2 and ZrO2 were used to measure neutron fluence-to-kerma conversion coefficients at energies up to 66 MeV. The LPPCs served to measure the absorbed dose deposited in the gas of a cavity surrounded by the counter walls that could be converted to the absorbed dose to the wall on the basis of the Bragg-Gray cavity theory. Numerically the absorbed doses to the walls were almost equal to the corresponding kerma values of the wall materials. The neutron fluence was determined by various experimental methods based on the reference cross sections of the 1H(n, p) scattering and/or the 238U(n, f) reactions. The measurements were performed in monoenergetic neutron fields of energies of 5 MeV, 8 MeV, 15 MeV and 17 MeV and in polyenergetic neutron beams with prominent peaks of energies of 34 MeV, 44 MeV and 66 MeV. For the measurements in the polyenergetic neutron beams, significant corrections for the contributions of the non peak energy neutrons were applied. The fluence-to kerma conversion coefficients of N and O were determined using the difference technique applied with matched pairs of LPPCs made from a chemical compound and a pure element. This paper reports experimental fluence-to-kerma conversion coefficient values of eight elements and four compounds measured for seven neutron energies, and presents a comparison with data from previous measurements and theoretical predictions. The distributions of the absorbed dose as a function of the lineal energy were measured for monoenergetic neutrons or, for polyenergetic neutron fields, deduced by applying iterative unfolding procedures in order to subtract the contributions from non-peak energy neutrons. The dose distributions provide insight into the neutron interaction processes.     

Recessive, sex-I inked, progressive, oculocerebral degeneration

Norrie's disease is a rare condition with a recessive sex-linked mode of inheritance, blindness with progressive ocular degeneration, and mental retardation of varying severity. Deafness and epilepsy may occasionally occur.
The findings in a 42-year-old, male, mentally retarded patient suffering from Norrie's disease are reported. His family tree is noted and the differential diagnosis of this condition is discussed.     

Macroscopic, histologic, histochemical, immunohistochemical, and ultrastructural features of mesothelioma

Mesotheliomas are uncommon neoplasms that arise from the cells forming the serosal membranes of the body cavities. Approximately 90-95% of mesotheliomas arise in the pleural cavity and 5-10% in the peritoneal cavity. Rare mesotheliomas arise in the pericardium and in the tunica vaginalis. Unlike many neoplasms, mesotheliomas grow in a diffuse distribution and tend to encase the organs in the various body cavities. A combination of histochemical, immunohistochemical, and ultrastructural features are often necessary to accurately diagnose mesotheliomas. These techniques are highlighted in this review article on mesothelioma.