Selective rod degeneration and partial cone inactivation characterize an iodoacetic acid model of Swine retinal degeneration

PURPOSE. Transgenic pigs carrying a mutant human rhodopsin transgene have been developed as a large animal model of retinitis pigmentosa (RP). This model displays some key features of human RP, but the time course of disease progression makes this model costly, time consuming, and difficult to study because of the size of the animals at end-stage disease. Here, the authors evaluate an iodoacetic acid (IAA) model of photoreceptor degeneration in the pig as an alternative model that shares features of the transgenic pig and human RP. METHODS. IAA blocks glycolysis, thereby inhibiting photoreceptor function. The effect of the intravenous injection of IAA on swine rod and cone photoreceptor viability and morphology was followed by histologic evaluation of different regions of the retina using hematoxylin and eosin and immunostaining. Rod and cone function was analyzed by full-field electroretinography and multifocal electroretinography. RESULTS. IAA led to specific loss of rods in a central-to-peripheral retinal gradient. Although cones were resistant, they showed shortened outer segments, loss of bipolar cell synaptic connections, and a diminished flicker ERG, hallmarks of transition to cone dysfunction in RP patients. CONCLUSIONS. IAA provides an alternative rod-dominant model of retinal damage that shares a surprising number of features with the pig transgenic model of RP and with human RP. This IAA model is cost-effective and rapid, ensuring that the size of the animals does not become prohibitive for end-stage evaluation or therapeutic intervention.     

Fracture resistance and gap formation of MOD restorations: influence of restorative technique, bevel preparation and water storage

This in vitro study evaluated the effect of technique, use of a bevel and thermal cycling on the fracture resistance and gap formation of resin composite MOD restorations. Fracture resistance was measured on standard MOD cavities prepared in 100 upper premolars that were stored for 24 hours and 6 months with 1000 thermal cycles. Subgroups (n=10) were: beveled or non-beveled preparations and direct restorations (Adper Single Bond/Filtek Z250) and indirect restorations (prepolymerized Filtek Z250 cemented with Rely XARC). Ten sound teeth and 10 specimens with MOD preparations without restorations served as the positive and negative controls, respectively. The specimens were subjected to axial compression in a universal testing machine at a crosshead speed of 0.5 mm/minute. Failure patterns were analyzed by stereomicroscopy (40x). To evaluate gap presence or absence, proximal box cavities were prepared in 24 human third molars that were restored as described above. The specimens were evaluated under SEM examination after 24 hours and six months. Data were statistically analyzed by ANOVA and multiple comparison tests at the 0.05 level of significance. After 24 hours, the beveled restorations exhibited higher fracture strength values than the non-beveled restorations, and all groups showed resistance similar or superior to sound teeth. After six months, the highest fracture resistance was obtained for beveled inlays and the lowest values were observed for direct restorations with butt joints. Thermal cycling decreased fracture resistance in the majority of the groups. The main fracture pattern observed was cohesive failure in the material, but adhesive failures increased over time, especially in the non-beveled restorations. Under SEM examination, no difference was observed among the groups after 24 hours. However, after six months, the beveled restorations exhibited no gap formation. It was concluded that storage with thermal cycling decreased fracture resistance, bevels improved fracture resistance and, in general, indirect restorations were not superior to direct restorations.     

Hepatic malignancies: improved treatment with intraarterial Y-90

An improved treatment method for hepatic malignancies with yttrium-90 incorporated into the matrix of glass microspheres was evaluated prospectively. Fifteen patients with 12 metastatic colorectal cancers, one carcinoid, one islet cell tumor, and one hepatoma were treated with three dose levels: 5,000 cGy (5,000 rad), ten patients; 7,500 cGy (7,500 rad), three patients; and 10,000 cGy (10,000 rad), two patients. Mean follow-up was 7 months (range, 2-12 months). Stable disease in the liver was seen in ten patients, four of whom had concurrent progression of extrahepatic disease, which resulted in two deaths. Two additional deaths were not directly related to the malignant process. Progression of liver disease was found in five patients, with three deaths occurring at 7-8 months. No procedural, hematologic, or pulmonary complications occurred. Late gastroduodenal ulceration occurred at 6-8 weeks in three patients who had histories of chronic alcohol abuse. This method of therapy seems to be feasible and efficient. Caution is necessary with high doses or with patients with a history of or predisposition to gastroduodenal ulcers.     

Pontine and basal forebrain cholinergic interaction: implications for sleep and breathing

Pontine and forebrain cholinergic nuclei contribute to the regulation of breathing and arousal. This report summarizes experiments in rat (n = 20) concerning the cholinergic interaction between pons and basal forebrain. In vitro [(35)S]guanylyl-5'-O-(gamma-thio)-triphosphate ([(35)S]GTPgammaS) autoradiography quantified carbachol-stimulated guanine nucleotide binding (G) protein activation in seven basal forebrain nuclei. Carbachol significantly increased [(35)S]GTPgammaS binding in the vertical and horizontal limbs of the diagonal band of Broca, medial and lateral septum, and nucleus basalis (B)/substantia innominata (SI). In vitro receptor autoradiography demonstrated muscarinic receptors in the same nuclei where carbachol caused G protein activation. In vivo experiments showed that carbachol administered to the pontine reticular formation (PnO) significantly decreased the number of 7-14Hz spindles in the electroencephalogram (EEG), decreased acetylcholine release in SI, and decreased respiratory rate. Carbachol microinjection into SI did not alter the number of EEG spindles or respiratory rate. The results help clarify that EEG and rate of breathing are more effectively modulated by cholinergic neurotransmission in PnO than in SI.     

One-year clinical evaluation of two polyacid-modified resin composites (compomers) in posterior permanent teeth

PURPOSE: The aim of this study was to evaluate the clinical performance of two polyacid-modified resin composites (Dyract AP and F2000) in posterior teeth after 1 year of clinical service. MATERIALS AND METHODS: Seventy-two Class I restorations were performed in 33 patients (average age 25 years) by one operator. Eighty-two per cent of the restorations were located in molars. Before the proceedings, patients were informed about the aim of the study and they gave written consent to participate. At least one restoration of each material was placed in each individual. The materials were applied according manufacturer's instructions. Following finishing and polishing, one examiner performed the clinical baseline examination using the adapted USPHS system. To be included in the clinical trial, a restoration had to be rated "Alpha". After one year, 25 patients were recalled and 56 restorations were evaluated using the adapted USPHS system. RESULTS: All restorations were classified as clinically satisfactory (Alpha or Bravo). However, there was a decrease in restoration quality compared to baseline. Statistical analysis (chi2 and Fisher's exact test) demonstrated differences only in relation to superficial roughness, with exhibiting F2000 more surface roughness than Dyract AP (p < 0.01). CONCLUSION: Based on the methodology employed, all restorations were satisfactory after one year and the two materials performed similarly, except for the surface roughness criteria.     

Prenatal diagnostic decision-making in adolescents

STUDY OBJECTIVE: We sought to evaluate the prenatal decision-making of pregnant adolescents identified at increased risk for identifiable fetal genetic abnormalities. DESIGN: A retrospective review of records of gravid women 19 years old or younger undergoing genetic counseling from 2001-2003 (inclusive) was undertaken. SETTING: Hospital-based academic center. PARTICIPANTS: Thirty-seven women were identified; four cases did not meet inclusion criteria. INTERVENTIONS: None. MAIN OUTCOME MEASURE: Decision to undergo or forgo invasive prenatal testing. RESULTS: Of the 33 women included in this study, the average age was 17.6 years (range: 15-19). Eighteen were Latinas, eight were African-Americans, and seven were Caucasians. Sixteen women had positive maternal serum screening outcomes; nine women sought counseling because of personal/family histories of genetic abnormalities, seven sought counseling after fetal structural anomalies were detected by ultrasound, and one woman sought counseling because she and her partner were positive for Mendelian disorder screening (sickle cell disease). Sixteen of the women (48.5%) chose to undergo invasive testing (15 amniocenteses, one chorionic villus sampling) whereas 17 (51.5%) chose to forgo invasive testing. CONCLUSIONS: Adolescents offered invasive prenatal diagnosis will chose to undergo or forgo such testing based on diagnostic and personal criteria as do adult women. Nonetheless, unique adolescent issues may make the process by which information is obtained and communicated during counseling to be different from counseling provided to adults. The development of new genetic screening and diagnostic protocols has and will increase the number of pregnant adolescent women who will be offered genetic counseling during their pregnancies. Such an increase in numbers will place considerably more pressure on an already taxed genetic counseling system; accordingly, new counseling paradigms will need to be developed to provide service to an expanded patient population seeking information for an increasing number of genetic issues.     

Artificial rearing of mouse pups: development of a mouse pup in a cup model

Artificial rearing of rat pups has been used in the investigation of the neonatal gut. We propose to adapt the model of artificially rearing rat pups for use in mouse pups, thereby allowing the use of transgenic animals for our research. We hypothesized that gastrostomy catheters may be placed successfully into neonatal mouse pups and that the pups may be artificially reared without significant alterations in their growth or intestinal development. Gastrostomy tubes are placed into 5-d-old mouse pups [artificially reared (AR); n = 32], and the mice are fed rodent milk substitute. Littermate pups [maternally reared (MR); n = 22] are used as controls. After 5 d, pups are killed and their organs are harvested. Intestinal villus measurements, protein content, and DNA content are determined. Data are reported as mean +/- SEM, compared with appropriate statistical methods, and significance is determined at P < 0.05. Initial weights and lengths are not different between the two groups, but after 5 d, MR pups weigh more than their AR counterparts (5.0 +/- 0.13 versus 4.1 +/- 0.14 g, MR versus AR; P < 0.01). However, the pups' length and the intestinal villus height-to-width ratios, protein, and DNA content are not different between the MR and AR pups. To our knowledge, this is the first report of artificially rearing mouse pups. Development of this technique will permit nutritional manipulation in neonatal mice, a mammalian model wherein the genome is sequenced and transgenic mutants are available.     

The enhanced tumor selectivity of an oncolytic vaccinia lacking the host range and antiapoptosis genes SPI-1 and SPI-2

The ability of cancer cells to evade apoptosis may permit survival of a recombinant vaccinia lacking antiapoptotic genes in cancer cells compared with normal cells. We have explored the deletion of two vaccinia virus host range/antiapoptosis genes, SPI-1 and SPI-2, for their effects on the viral replication and their ability to induce cell death in infected normal and transformed cells in vitro. Indeed, in three paired normal and transformed cell types, the SPI-1 and SPI-2 gene-deleted virus (vSP) preferentially replicates in transformed cells or p53-null cells when compared with their normal counterparts. This selectivity may be derived from the fact that vSP-infected normal cells died faster than infected cancer cells. A fraction of infected cells died with evidence of necrosis as shown by both flow cytometry and detection of high-mobility group B1 protein released from necrotic cells into the culture supernatant. When administered to animals, vSP retains full ability to replicate in tumor tissues, whereas replication in normal tissues is greatly diminished. In a model of viral pathogenesis, mice treated with vSP survived substantially longer when compared with mice treated with the wild-type virus. The mutant virus vSP displayed significant antitumoral effects in an MC38 s.c. tumor model in both nude (P < 0.001) and immunocompetent mice (P < 0.05). We conclude that this recombinant vaccinia vSP shows promise for oncolytic virus therapy. Given its enhanced tumor selectivity, improved safety profile, and substantial oncolytic effects following systemic delivery in murine models, it should also serve as a useful vector for tumor-directed gene therapy.     

Tinea Capitis in Adults

Tinea capitis is regarded as rare in healthy adults. A study of 46 adults presenting with scalp problems with no other identifiable cause and 26 asymptomatic adult contacts of children with tinea capitis was undertaken. The confirmation of tinea capitis in 9 of 46 patients and 5 carriers among 26 adult contacts suggests that tinea capitis may affect healthy adults more often than was supposed. Further epidemiologic studies may be of interest.     

Establishment and characterization of a human myeloid cell line from Philadelphia chromosome-negative myeloblastic leukemia arising in a patient with myelodysplastic syndrome

A new hematopoietic cell line derived from a patient with Philadelphia chromosome (Ph1)-negative myeloblastic leukemia arising from a form of myelodysplastic syndrome (MDS) is described. This cell line, designated TMM, consists of immature cells with the morphological characteristics of young myeloblasts and grows in suspension culture with a doubling time of about 30 hours. By cytochemical analysis the cultured cells were positive for acid phosphatase. They were free of the Epstein-Barr virus-associated nuclear antigen as well as terminal deoxynucleotidyl transferase. Further phenotypic analysis revealed the expression of the myelomonocytic-specific antigen Leu-M1 and receptors for the Fc portion of IgG. Partial differentiation of these cells could be induced by dimethyl sulfoxide, tetradecanoyl phorbol acetate, or hypoxanthine and resulted in cells of the myeloid series expressing lysozyme and receptors for the C3b complement protein. The karyotype was 46,XY, lacked the Ph1 chromosome, and displayed no abnormalities at the light microscopic level. No rearrangement of the bcr-c-abl gene complex was found. This cell line should be useful for studying an important type of the heterogeneous population constituting Ph1-negative myeloblastic leukemia, arising in this instance from MDS, as well as for studying differentiation and proliferation of human pluripotent stem cells.