Deletion mutation in an eye lens beta-crystallin. An animal model for inherited cataracts

The most prevalent proteins in the lens of the eye are called crystallins, and it is thought that aberrant crystallins may cause opacification of lens tissue. The Philly mouse, a strain with an inherited cataract, has an abnormal beta B2-crystallin, the principal beta-crystallin in the mouse. The cDNA that codes for the beta B2-crystallin protein has been cloned and sequenced from both the normal and the cataractous Philly mouse. The normal mouse beta B2 cDNA is 756 nucleotides in length with 618 nucleotides of open reading frame. An in-frame deletion of 12 nucleotides has occurred in the Philly mouse cDNA, which results in the loss of 4 amino acids. The sequence of the mutant beta B2 was analyzed against the reported structure of the normal bovine beta B2-crystallin determined by x-ray crystallography. The region, in which the deletion of the amino acids occurs near the COOH terminus, is essential for the formation of the tertiary structure of the beta B2-crystallin. The loss of these residues could explain the alterations that are seen with the Philly beta B2 protein and may account for the instability of the Philly beta B2 protein. This abnormal beta B2-crystallin may be the cause of the cataract in this animal.

Interaction of an altered beta-crystallin with other proteins in the Philly mouse lens

An altered beta B2-crystallin is synthesized in the lens of the Philly mouse. This beta B2 has a more acidic isoelectric point than the beta B2 that is isolated from normal mouse lens. The altered beta B2 is immunologically reactive with antibody to the amino terminal of the beta B2-crystallin, but appears to be present in only very small quantities in the Philly lens. When the soluble proteins are isolated from the Philly lens and chromatographed by gel exclusion chromatography, the beta B2 can be found primarily in the heavy molecular weight fraction. Some immunoreactive material was also found throughout the higher molecular weight beta-crystallin region, beta H, and the lower molecular weight region, beta L. These results would indicate that the altered beta B2-crystallin in the Philly lens can interact with the other beta-crystallins in the lens; however, interactions of the beta B2-crystallin with the other proteins of the lens may cause rapid aggregation of the cellular proteins leading to the formation of the heavy molecular weight material. The increased number of these aggregates may eventually lead to the cataract formation in the Philly mouse.

Sequence and structure correlation of human ribosomal transcribed spacers

We report the sequences of the transcribed spacers of human rRNA that now allow us to piece together the entire primary transcript sequence of approximately 13.3 x 10(3) base-pairs. Comparison of transcribed spacer sequences with those of variable regions of rRNA and with those of the non-transcribed spacers supports the hypothesis that the variable regions are descended from transcribed spacers. Nucleotide sequence-derived secondary structures for the 5' external transcribed spacer and for internal transcribed spacers 1 and 2 match both the sizes and shapes of the structures that were visualized 15 years ago on electron micrographs. Parts of these structures are conserved in mammals and may be related to transcript processing.

Physicians' responses to diagnostic test guidelines

Internists (IM), subspecialty internists (SS), and family practitioners (FP) were surveyed regarding their opinions of ten of the Blue Cross Blue Shield Association/American College of Physicians diagnostic test use guidelines applied to the asymptomatic periodic health exam. The majority of 390 respondents agreed with the guidelines (59% of all responses). There was at least 40% disagreement with seven of ten guidelines. Board certification was associated with agreement. Internists and family practitioners were more likely to agree than subspecialty internists. The number of years in practice had a negative correlation with agreement for five guidelines. HMO physicians tended to agree with guidelines that discouraged test ordering. Results indicate that these guidelines for test use, based on research data and developed cooperatively by physicians, are a starting point for guidelines to testing during the periodic health examination.

Point mutation affecting processing of the ornithine aminotransferase precursor protein in gyrate atrophy

A generalized deficiency of the mitochondrial enzyme, ornithine aminotransferase (OAT) is the inborn error in gyrate atrophy, an autosomal recessive degenerative disease of the choroid and retina of the eye that leads to blindness. Southern analysis, using the OAT cDNA probe, of the OAT gene in a gyrate atrophy patient whose level of OAT protein is markedly decreased indicated the functional gene to be grossly intact. Northern analysis of his OAT mRNA demonstrated only half the normal level of OAT message, suggesting expression of only one of the two alleles of the OAT gene. A functional assay of the expressed OAT mRNA by in vitro translation and immunoprecipitation with anti-human OAT antibody indicated synthesis of an OAT protein from the message. The expressed message was cloned and sequenced and was shown to contain a single base change from C to T, resulting in an amino acid codon change from CAT (histidine) to TAT (tyrosine) at position 319 in the translated OAT protein. The mutant and normal OAT precursors were synthesized using transcriptional expression clones of OAT and in vitro translation of the expressed mRNA and tested in an in vitro mitochondrial transport/processing system. The results indicate that the mutant OAT precursor from the gyrate atrophy patient can be transported to the mitochondria but is minimally processed there, which would lead to degradation of the labile precursor and loss of OAT activity as phenotypically observed.

Dizziness and perceptual style

This study tested the hypothesis that patients suffering from non-organic ('psychogenic') dizziness would score higher on Witkins' frame dependence test than a group of dizzy patients with peripheral organic damage. A computerized version of the portable rod and frame test was administered to a group of 10 chronic ENT patients with peripheral vestibular disease, 10 ENT patients with no detectable organic problems and 10 non-dizzy controls. Contrary to the hypothesis, the psychogenic group had less frame-dependent error than the peripheral group and less (though not significantly so) than the normal group. Four of the psychogenic group had very low frame dependence scores. The experience of dizziness may not be necessarily related to anxiety proneness and may be a function of an inhibitory autonomous perceptual style as well as one overly dependent on external cues.

Allergy in asthma. II. The highly atopic infant and chronic asthma

The relationship between allergy and asthma in infants and preschool children was investigated. One hundred nine children, median age 2 1/2 years, were examined immunologically by quantitation of serum IgE, RAST testing to 13 allergens, and culture of peripheral blood lymphocytes for spontaneous IgE formation. We examined a cross-section of infants and toddlers to determine whether the severity of asthma is associated with allergy as has been reported in older children with asthma. We identified a group of highly atopic infants and preschool children who have serum IgE at least 10 times the mean + 1 SE for age, multiple positive RASTs with early formation of IgE to inhalant antigens, and circulating B cells that spontaneously form IgE when these are cultured in vitro. Such highly atopic infants and preschool children were statistically more likely to have chronic asthma requiring multiple continuous medication compared to the rest of the population (p less than 0.01).

Lymphocyte proliferation to antigen E: demonstration of the restriction of antigen E-specific T cells to ragweed-allergic donors

Allergic sensitivity to ragweed is common among atopic individuals in North America and can be associated with symptoms of seasonal hay fever and increased airway reactivity in asthma. This sensitivity is mediated by IgE antibody to ragweed antigens that in turn is presumed to be the product of B-lymphocytes regulated by various T cell subsets. Proliferation in vitro by lymphocytes obtained from individuals allergic to ragweed and cultured in the presence of ragweed antigen E (AgE) has been repeatedly described, but a comprehensive study of this proliferation has questioned the specificity of this response. We have examined this question and found that in the first week of culture, the specific lymphocyte proliferation to AgE may be obscured by high background and mitogen-like proliferation. However, by carrying the cells for a longer period of time in culture and providing a second in vitro boost with AgE, specific proliferation could be clearly documented. Lymphocytes from atopic ragweed-allergic donors proliferated at levels 20 to 50 times beyond background in the presence of AgE. Cells from nonragweed-allergic donors (either nonatopic or atopic) did not do so. The AgE-responsive cells could be expanded in culture and demonstrated to be T cells. Moreover, AgE-responsive T cells could only be cloned from AgE-allergic donors and, after expansion and subcloning, demonstrated to respond to AgE but not partially purified dust mite antigen. In contrast, a clone of T cells from a dust mite-sensitive individual proliferated in response to the dust mite antigen but not AgE.

Neurospora crassa ribosomal DNA: sequence of internal transcribed spacer and comparison with N. intermedia and N. sitophila

Using [32P]DNA probes from a clone containing 17S, 5.8S and 26S rRNA of Neurospora crassa, the remainder of the repeat unit (RU) for ribosomal DNA (rDNA) has been cloned. Combining restriction analysis of the cloned DNA and restriction digests of genomic DNA, the RU was found to be 8.7 kb. The nucleotide sequence was determined for the internal transcribed spacer (ITS) regions one and two, for 5.8S rRNA and for portions of 17S and 26S rRNAs immediately flanking the ITS regions, and compared to the corresponding region of Saccharomyces carlsbergensis. In addition, a comparative restriction analysis of two other Neurospora species was performed using twelve restriction endonucleases. Genomic DNA blots of rDNA from N. intermedia and N. sitophila revealed rDNA RUs of 8.4 kb. The majority of differences in restriction patterns were confined to sequences outside the mature rRNA regions. However, one SmaI recognition site was found in 26S rRNA of N. crassa and N. sitophila but not in N. intermedia.

A comparison of different methods for assessing the 'intensity' of tinnitus

Questions are raised about the technical and psychological interpretation of loudness match measures in the assessment of tinnitus "intensity". The effect of hearing threshold on loudness matches expressed in sensation level (SL) was investigated by selecting subjects with different degrees of hearing loss. The loudness match expressed in SL was found to be a function of threshold. Correlations were then determined between psychological scales of tinnitus complaint (reported loudness, distress, intrusiveness, and others) and loudness match expressed in HL, SL, sones, or personal loudness units (PLUs). Only matches expressed in PLUs were significantly correlated with reported loudness or other psychological scales. The PLU transformation, derived from an individually determined loudness function, produces values that are generally independent of other audiometric measures. It is therefore recommended for assessing tinnitus "intensity".

A factor analytical study of tinnitus complaint behaviour

Two separate factor analyses were conducted on various self-rated complaints about tinnitus and related neuro-otological symptoms, together with audiometric measurements of tinnitus 'intensity' (masking level and loudness matching levels). Two general tinnitus complaint factors were identified, i.e. 'intrusiveness of tinnitus' and 'distress due to tinnitus'. 3 specific tinnitus complaint factors were also found, i.e. 'sleep disturbance', 'medication use' and 'interference with passive auditory entertainments'. Other neuro-otological symptoms and the audiometric measures did not load on these factors. An exception was provided by loudness matches at 1 kHz, which had a small loading on the 'intrusiveness of tinnitus' factor. Self-rated loudness had a high loading on this factor. Otherwise, the loudness (either self-rated or determined by loudness matching) was unrelated to complaint dimensions. The clinical implications of the multifactorial nature of tinnitus complaint behaviour are considered.

Coelomocyte motility

We have utilized a video-enhanced contrast system coupled to a DIC-equipped microscope to examine the motility of both whole coelomocytes and individual filopodia. When the cells are left in diluted coelomic fluid, they exhibit a fibroblast-like mode of translocation across the substrate. These cells extend lamellipodia at their advancing margin and develop retraction fibers at the trailing edge. Filopodia are actively extended from the lamellipodia of the advancing margin. Cells that are washed free of the coelomic fluid and placed in an isotonic buffer lose their ability to translocate. Filopodia on these stationary cells are seen to undergo a series of waving and bending motions. These motions are rapid and result in a filopodium folding back upon itself only to re-extended later. Both forms of motility are discussed in light of the existing structural and biochemical knowledge of this and other cell types.

Development of the structural components of the brush border in absorptive cells of the chick intestine

The spatial and temporal relationships between cytoplasmic filaments and the morphogenesis of the intestinal brush border were examined by transmission electron microscopy of normally developing tissue and of tissue exposed to a variety of experimental conditions in organ culture. Distinct stages in the development of the brush border were identified: (1) Irregular projections of the apical plasma membrane that contain a network of microfilaments are converted to uniform projections filled with a core bundle of straight microfilaments (7-11d of incubation). (2) Rootlets form by an elongation or aggregation of filaments (11-15d). (3) The terminal web forms first as a network of short filaments just below the apical plasma membrane, then secondarily stratifies into two layers (19d of incubation to 3d posthatching). (4) Core filaments elongate as microvilli achieve their maturity (21d of incubation to 5d posthatching). Microvillus formation was not perturbed by culturing 9d tissue in high concentrations of Ca++ or Mg++, either with or without the ionophore, A23187. Rootlet formation was stimulated by high Mg++, with or without A23187, and, for reasons unknown, by ethanol. Terminal web formation was not stimulated by Mg++ or Ca++, but the integrity of the terminal web was lost when 21d embryonic tissue was cultured with EGTA or cytochalasin B. After stratification, the terminal web could not be disrupted by EGTA, but instead was aggregated to the center of the apical end of the cell.

Controlled studies of the acute antidepressant effects of lithium

In two randomized double-blind controlled trials on 63 depressed female in-patients subject to recurrent affective disorder (bipolar and unipolar manic-depressive psychosis) lithium was shown to have major acute antidepressant effects. At the end of three weeks lithium produced more uniform improvement than did imipramine; lithium in combination with tryptophan (in the form of Optimax) was superior to tryptophan alone--the latter drug having no discernible antidepressant activity in this group of patients. Lithium did not produce an antidepressant effect until the second and third week of both trials.

Clinical evaluation of the MICRO-ID, API 20E, and conventional media systems for identification of Enterobacteriacea

MICRO-ID (General Diagnostics, Morris Plains, N.J.) is a new kit system designed for the identification of Enterobacteriaceae in 4 h. It consists of 15 biochemical tests of paper disks. Each test is in its own compartment in a molded plastic tray. Only one reagent need be added to the system (2 drops of 20% KOH, which is added to the Voges-Proskauer test). Based on the pattern of positive and negative biochemical test results, a five-digit octal code number is calculated. An identification is derived from a computer-generated identification manual. A study was conducted to compare three systems-the MICRO-ID 4-h and the API 20E (Analytab Products Inc., Plainview, N.Y.) 18- to 24-h systems and a conventional media system-to measure the ability of each to identify members of the family Enterobacteriaceae. Comparison tables, rather than simple percentage agreement tables, were generated to define the particular strengths and weaknesses of each system and allow the laboratory to best use the data. The MICRO-ID compared quite favorably with conventional media. MICRO-ID yielded incorrect identifications with 1.5% of the isolates tested (API 20E, 4.7% misidentification rate). Half the MICRO-ID misidentifications occurred when the system identified a Citrobacter diversus as a lysine-negative Escherichia coli; all gave one octal number. A direct comparison of the MICRO-ID and API 20E was of limited value because percentage agreements were merely the sums of the errors of each. The ease of inoculation, the requirement for the addition of only one reagent, and the 4-h capability make the MICRO-ID system an extremely attractive development in the field of bacterial identification.

Credibility of smoking control strategies in non-smokers: implications for clinicians

The credibility of rapid smoking, relaxation, covert sensitization, satiation, and a combined approach was assessed in 113 subjects who were self-reported non-smokers. The results suggest that non-smokers more than smokers rate with greater variability strategies for smoking treatment favoring relaxation significantly over the other treatments examined. It also appears that satiation was least preferred when compared with descriptions of other treatments. These findings, while similar to those reported for smokers, suggest that significant others who do not smoke may likely support the positive treatment expectations of those who undergo treatment for the control of smoking.

Erythropoiesis and erythrocytic survival in dogs with cyclic hematopoiesis

Erythrocytic survival and ferrokinetic studies were carried out in dogs with cyclic hematopoiesis. The serum iron values varied during different phases of the cycle. The highest values occurred when the bone marrow predominantly contained granulocytic cells. The erythrocytic survival and the remainder of the ferrokinetic variables were comparable to those in normal dogs of a similar age.