Fusarium oxysporum f. sp. mori, a New Forma Specialis Causing Fusarium Wilt of Blackberry.

Fusarium oxysporum has recently been identified as the cause of a wilt disease affecting blackberry in California and Mexico. Thirty-six isolates of F. oxysporum obtained from symptomatic blackberry plants in California and Mexico were comprised of nine distinct somatic compatibility groups (SCGs). Phylogenetic analysis of a concatenated data set, consisting of sequences of the translation elongation factor 1-α and ß-tubulin genes and the intergenic spacer of the ribosomal DNA, identified nine three-locus sequence types, each of which corresponded to an SCG. Six SCGs were present only in California, two only in Mexico, and one in both California and Mexico. An isolate associated with the most common SCG in California was tested for pathogenicity on blueberry, raspberry, strawberry, and lettuce. All blueberry, raspberry, and lettuce plants that were inoculated remained healthy, but two of the five strawberry cultivars tested developed symptoms. The three strawberry cultivars that were resistant to the blackberry pathogen were also resistant to F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry. We propose to designate strains of F. oxysporum that are pathogenic to blackberry as Fusarium oxysporum f. sp. mori forma specialis nov.

Immunological features of neurological paraneoplastic syndromes.

Neurological paraneoplastic syndromes are a rare group of disorders that occur in 1-2% of people with malignancy. They are usually caused by an immune response, triggered by and directed against a tumour, that cross-reacts with protein expressed by the peripheral or central nervous system. Any part of the nervous system can be affected and patients often develop severe and permanent disability. Diagnosis can be difficult as in two-thirds of patients the neurological problems appear up to 5 years before the tumour manifests. However, certain of these syndromes are often associated with specific serum autoantibodies that can be useful both in diagnosis of the neurological syndrome and in focusing the search for a particular tumour. Thus, these antibodies can allow earlier identification and treatment of cancer and, potentially, a reduction in morbidity and mortality. It was only in the 1980s that the first anti-neuronal autoantibodies were characterized and their associations with clinical syndromes and tumours defined. Further antibodies have been isolated over the past 20 years and novel pathogenic mechanisms for several syndromes have been recognized. For example, voltage-gate ion channels seem to be a common target for autoantibodies involved in peripheral nerve diseases such as the Lambert-Eaton myasthenic syndrome and neuromyotonia (Isaacs' syndrome). However, the place of most paraneoplastic antibodies in the pathogenesis of central syndromes is yet to be fully elucidated.

Neurological presentation of Fabry's disease in a 52 year old man.

Fabry's disease is an X linked inborn error of metabolism due to deficient activity of the lysosomal enzyme alpha galactosidase A. Previously unrecognised Fabry's disease presenting in a 52 year old man being investigated for progressive dysarthria and ataxia is discussed. Brain magnetic resonance imaging suggested the presence of small vessel disease but skin biopsy (done to exclude cerebral autosomal dominant arteriopathy with subcortical infarcts and leucencephalopathy) showed typical changes of Fabry's disease. This diagnosis was confirmed by subsequent enzyme assays. The authors contend that Fabry's disease should be excluded, at least on clinical grounds, in patients with otherwise unexplained cerebrovascular disease.

Intraspinal oxidised cellulose (Surgicel) causing delayed paraplegia after thoracotomy--a report of three cases.

Oxidised regenerated cellulose (Surgicel) is a commonly used haemostatic agent in neurosurgery, thoracic surgery, and orthopaedics. We present three cases of paraplegia after thoracic surgery during which oxidised cellulose had been used during thoracotomy for haemorrhage control, and was later found to have passed through the intervertebral foramen causing spinal cord compression. In all intraspinal and perispinal procedures, the over-liberal use of Surgicel should be avoided, and attempts made to remove all excess Surgicel once adequate haemostasis is obtained.

Aberrant expression of G(1)/S regulators is a frequent event in sporadic pituitary adenomas.

Components of the pRb/p16/cyclin D1/CDK4 pathway are frequent targets in numerous tumour types, including those of pituitary origin. However, previous studies of pituitary tumours have examined individual components of this pathway. Therefore, to determine their overall contribution we have simultaneously examined the immunohistochemical status of pRb, p16 and cyclin D1 and analysed the CDK4 gene for a characterized activating mutation. Of the total pituitary tumour cohort (29 clinically non-functioning adenomas and 16 somatotrophinomas) abnormal expression of either pRb, p16 or cyclin D1 was observed in 36 of 45 (80%) tumours and was significantly (P = 0.005) associated with non-functioning tumours (27/29; 93%) compared with somatotrophinomas (9/16, 56%). Loss of either pRb or p16 expression was mutually exclusive in 23 of 45 (51%) tumours, whilst concomitant loss of pRb and p16 expression was observed in five tumours. Cyclin D1 overexpression was observed in 22 of 45 (49%) tumours, however, there was no significant association between overexpression of cyclin D1 and the expression status of either pRb or p16. In addition, no activating mutations within codon 24 of the CDK4 gene were detected. This study provides evidence for the first time that components of the pRb/p16/cyclin D1/CDK4 pathway, either alone or in combination, are frequently deregulated in human pituitary tumours, suggesting that this pathway may be a useful target in drug or gene therapeutic approaches.

Analysis of cyclin D1 (CCND1) allelic imbalance and overexpression in sporadic human pituitary tumors.

Cyclin D1 plays an important role in the regulation of cell progression through G1 of the cell cycle and has been demonstrated to have oncogenic properties. Using RFLP-PCR, an A/G polymorphism within the cyclin D1 (CCND1) gene was analyzed in 151 sporadic human pituitary tumors, of which 60 were informative at this locus. Further analysis showed that in 15 of 60 (25%) tumors, there was evidence of allelic imbalance, which is indicative of gene amplification. Allelic imbalance was observed more frequently in invasive tumors (11 of 29 tumors; 38%) than in their noninvasive counterparts (4 of 31 tumors; 13%; P = 0.02). Forty-six of the tumors informative for the polymorphism were available for immunohistochemical analysis. Cyclin D1 expression (nuclear and/or cytoplasmic) was detected in 25 of 46 (54%) tumors. Of these cases, expression of nuclear cyclin D1 was detected in 9 of 46 (20%) tumors, whereas 16 of 46 (35%) tumors showed cyclin D1 staining exclusively confined to the cytoplasm. Neither nuclear staining nor cytoplasmic staining was observed in any of the normal pituitaries or in the negative control. Expression of cyclin D1 was observed in significantly more nonfunctional tumors (18 of 27 tumors; 67%) than in somatotrophinomas (7 of 19 tumors; 37%; P = 0.046). Nuclear cyclin D1 expression was observed more frequently in nonfunctional tumors (8 of 27 tumors; 30%) than in somatotrophinomas (1 of 19 tumors; 5%; P = 0.04). There was no correlation between cyclin D1 expression and tumor grade or between allelic imbalance of CCND1 and cyclin D1 expression. We conclude that amplification of CCND1 occurs in pituitary tumors and that the overexpression of cyclin D1 may be an early event in tumorigenesis. Cyclin D1 overexpression occurring in the absence of CCND1 allelic imbalance suggests that additional mechanisms responsible for deregulated cyclin D1 expression are involved in human pituitary tumorigenesis.

Effect of refrigeration on shear bond strength of three dentin bonding systems.

PURPOSE: To determine whether use of dentin bonding agents directly from refrigerated storage would have adverse effects on their shear bond strength to dentin. MATERIALS AND METHODS: Resin-based composite cylinders were bonded to dentin on the ground occlusal surfaces of 60 extracted human molars using three different dentin bonding systems at 3.0 degrees C and 23.5 degrees C. The cylinders were then debonded using an Instron testing machine in compression mode at 0.5 mm/sec. The results were interpreted with t-test and Student-Newman-Keuls post hoc analysis. RESULTS: Scotchbond Multi-Purpose demonstrated significantly lower shear bond strengths at 23.5 degrees C (P < 0.05) than all other groups at both 3.0 degrees C and 23.5 degrees C. All-Bond 2 and Prime & Bond had higher shear bond strengths at refrigerated temperature, but the differences were insignificant in magnitude.

Monoclonal antibodies against vascular endothelial antigens expressed in normal human brain.

A panel of monoclonal antibodies reactive with human-brain vessels was raised by immunizing BALB/c mice with homogenate of whole human brain, obtained from temporal lobectomies. Hybridoma supernates were screened by immunohistochemical methods on frozen sections of human brain, liver and spleen and 16 clones were isolated. The pattern of immunoreactivity varied with respect to the type of brain blood vessels predominantly labelled and to tissue specificity. Some antibodies cross-reacted with cow or squirrel monkey forebrain microvessels with an intensity equal to that shown by human brain. The immunoreactivity patterns reflected antigenic heterogeneity among different subsets of vascular endothelial cells in human brain.

At-home use of 35% carbamide peroxide bleaching gel: a case report.

When 10% carbamide peroxide is inefficient for stubborn stains and the patient experiences no sensitivity, higher concentrations (up to 35%) may resolve the discoloration.

Regaining space by using elastic orthodontic separators.

When an extensive carious lesion is present, interproximal space may be lost due to drifting of adjacent teeth. This may encroach upon the space needed to restore the tooth to proper occlusal and interproximal contours. Although the space may be regained with conventional orthodontics, this may not be an option in some cases due to financial or technical considerations. The outlined clinical technique uses elastic orthodontic separators in conjunction with an incrementally modified acrylic crown to regain lost interproximal space. The results of this technique were achieved rapidly and allowed for the placement of a physiologically contoured restoration. This procedure is technically simple, provides quick results, and is less expensive for the patient than conventional orthodontics.

The effect of water contamination on dimensional change and corrosion properties of a gallium alloy.

OBJECTIVE: This aim of this study was to determine the effect of water contamination on the dimensional change over time and the corrosion properties of a gallium-based alloy (Galloy, SDI), compared to an amalgam (Tytin, Kerr). METHODS: Normal and water-contaminated (10 microL of dH2O during condensation) Galloy and Tytin samples were fabricated using a split metal mold and mechanical condenser. The normal samples were tested for dimensional change under dry and wet (immersed in dH2O) conditions. The water-contaminated samples were tested for dimensional change under only dry conditions. Linear measurements were made over a 7 day period using a stage-equipped dial micrometer. The corrosion potential (Ecorr), the corrosion current density (lcorr), the passive current density (lp), the protective scale formation current density (lps) and potential (Eps), and the breakdown potential (Ebd) were obtained from the polarization curves generated in oxygenated saline solution. Single factor ANOVA and Duncan's multiple range tests were used to determine differences between the various samples. RESULTS: The water-contaminated Galloy samples contracted to a minimum of -3.42 +/- 1.73 microns cm-1 in 5 h followed by expansion to a maximum of 22.56 +/- 3.90 microns cm-1 at the end of 7 days. Normal Galloy and Tytin samples and water-contaminated Tytin samples exhibited rapid contraction during the first 24 h, followed by minimal change over the next 7 days. The Ecorr of normal and water-contaminated Galloy samples was more active than that of the normal and water-contaminated Tytin samples. The lcorr of the normal and water-contaminated Galloy samples was three orders of magnitude greater than the lcorr of normal and water-contaminated Tytin samples. The Eps for the water-contaminated Galloy and Tytin samples was more noble than for the normal Galloy and Tytin samples. The Ebd for the Tytin and water-contaminated Tytin samples was greater than the corresponding values for the Galloy and water-contaminated Galloy samples. SIGNIFICANCE: The gallium-based alloy exhibited expansion if contaminated with water during the condensing and setting process. Post-setting exposure to water did not result in expansion of the gallium-based alloy. The alloy also exhibited a greater susceptibility to corrosion than the amalgam. Due to the possibility of delayed expansion, this material should be used cautiously, particularly in applications involving weakened tooth structure.

Allelic deletion in pituitary adenomas reflects aggressive biological activity and has potential value as a prognostic marker.

Tumors of the pituitary gland are usually benign adenomas and account for 10% of all intracranial neoplasms. Five pituitary tumors have previously been reported to harbor multiple allelic deletions. Of these, three displayed particularly aggressive biological behavior, whereas there were no clinical details provided for the others. This study was designed to test the hypothesis that genetic deletions are a marker of invasive behavior and to identify the loci most commonly involved. Accordingly, we studied two cohorts of pituitary tumors, classified radiologically as invasive or noninvasive, for loss of heterozygosity (LOH). There is a significantly higher frequency of LOH in invasive tumors (10.8% of all loci examined) compared to noninvasive tumors (2.4%; P < 0.001). Of the 11 loci investigated, 75% of the allelic deletions identified in invasive tumors were found at 4 loci: 11q13, 13q12-14, 10q, and 1p. Twenty of 47 invasive tumors had evidence of at least 1 allelic deletion, whereas 14 of 20 had more than 1. Of the 6 tumors with only 1 deletion, 5 involved the 11q13 locus, suggesting that this is an early change in the transition from noninvasive to invasive adenoma. Comparison of invasive and noninvasive tumors demonstrates a significantly higher frequency of deletions affecting 11q13 (P < 0.001), 13q12-14 (P < 0.05), and 10q26 (P < 0.05) in invasive tumors. In addition, allelic deletion correlates with increasingly invasive behavior (modified Hardy classification), as 73% of grade 4 tumors compared to 33% of grade 3 and 9.5% of grade 1 and 2 tumors demonstrated LOH at any locus. Furthermore, in some tumors we identified a breakpoint between markers intragenic and extragenic to the retinoblastoma gene (Rb1) on chromosome 13q, suggesting that tumor suppressor genes other than or in addition to Rb1 may be involved in pituitary tumorigenesis. This was further supported by the presence of Rb protein in two of four tumors where the genetic loss extended to include the intragenic marker D13S153. Early identification of tumors with likely invasive potential by means of genetic analysis (LOH) may provide useful information on potential tumor behavior and aid tumor management in a manner that is not possible using routine histological methods. A large prospective study is required in patients without radiological evidence of invasion to assess the value of LOH in predicting outcome and for planning treatment.

Resistance to fracture of teeth with various preparations for amalgam.

OBJECTIVES: Advances in dental instrumentation and materials have allowed for increasingly conservative preparations when treating teeth for dental caries. Research has shown that some materials, properly used, can restore teeth to their pre-prepared strength. At the present time, the longevity of these materials is unknown, requiring clinicians to remain committed to conservative methods of tooth preparation. The purpose of this study is to compare the resistance to fracture of teeth prepared with occlusal, mesio-occlusal-distal (MOD) and mesial/distal slot preparations against unprepared control teeth. METHODS: Thirty-two non-carious, non-restored human maxillary premolar teeth were divided into three experimental groups and a control group with eight teeth in each. After preparation, the teeth were loaded to fracture on an Instron Universal Testing Machine, and the results were compared using an Analysis of Variance (ANOVA) followed by Tukey's Studentized Range Test (P < 0.05). Fracture patterns were compared by chi-square analysis at the 0.1 level of probability. RESULTS: There was no significant difference in fracture resistance among the experimental groups, but all were less resistant to fracture than the unprepared control group. The MOD and occlusal groups demonstrated a tendency towards vertical fracture while the mesial-distal slot and unprepared groups tended to a more limited fracture of a single cusp. CONCLUSIONS: Any preparation appears to decrease a tooth's resistance to fracture. Conservative preparation design may affect fracture pattern and enhance options for subsequent restoration.

Esthetics: patients' perceptions of dental attractiveness.

PURPOSE: The importance of dentofacial attractiveness to the psychosocial well-being of an individual has been well established. Very little information is available regarding dental patient perceptions of a pleasing esthetic image. The purpose of this study was to identify factors distinctive to attractive smiles versus unattractive smiles, as perceived by patients. MATERIALS AND METHODS: Standardized format photographs (5 x 7 in, matte finish, at f-32 and 1:2 magnification) of eight male and eight female smiles, framing only lips and teeth, were viewed by 297 subjects. The smiles exhibited differences in symmetry, tooth shade, number of teeth displayed, and height of maxillary lip line, and included both restored and unrestored teeth. Respondents ranked the photographs in order from most to least appealing appearance. Respondents viewed each series of photographs in a similar lighting and time period. A questionnaire identified the respondent's age, sex, race, education, income, and home town. Twenty-five demographic groups were established from the information in the questionnaire. Data were analyzed using stepwise discriminant analysis to determine the combination of smile characteristics that best predicted the ranking. RESULTS: The same female smile was chosen as the most attractive by 24 of the 25 demographic groups. This smile is characterized by natural teeth having light shade, high lip line, a large display of teeth, and radiating symmetry. Two female smiles typified by darker shade and asymmetry were rated by all groups as being least attractive. Two male smiles were judged equal as the most pleasing esthetically. Respondents favored those smiles characterized by light shade, a moderate display of teeth, moderate lip line, and a symmetrical arrangement of teeth. One male smile characterized by darker shade was rated as least attractive. CONCLUSIONS: In all cases, tooth shade was the most important factor, followed in sequence by unrestored natural teeth and number of teeth displayed. No correlation was found to exist between specific demographic groups and smile variables.

Clinical and genetic changes in a case of a Cushing's carcinoma.

A 30-year-old presented in 1984 with a clinically nonfunctional tumour which subsequently developed into a metastatic corticotrophinoma from which he died despite surgery in 1984, 1986 and 1991 and external radiotherapy in 1986. Molecular genetic analysis of tumour and metastatic tissue revealed loss of heterozygosity at loci on the autosomes 1p, 3p, 10q26, 11q13 and 22q12. Tissue taken at surgery in 1986 also revealed positive cytoplasmic immunostaining for p53 protein. No such staining was evident in tissue taken at first surgery in 1984. Further analysis of invasive pituitary adenomas may reveal loci associated with such behaviour, enabling better prediction of subsequent clinical outcome than is possible using standard histological techniques, and delivery of early, aggressive treatment to those tumours which show molecular markers associated with a poor prognosis.

P53 protein accumulates in Cushings adenomas and invasive non-functional adenomas.

The p53 protein, a negative regulator of cell growth, plays an important role in the pathogenesis of many human tumours following gene mutation and/or deletion. We screened a large number of sporadic pituitary tumours for p53 protein accumulation suggestive of gene mutation. Samples were divided into benign adenomas (n = 95) and invasive tumours with local or distant invasion (n = 26). All main tumour classes were represented. Putative p53 mutations were detected by immunohistochemistry on paraffin-embedded sections using polyclonal CM-1 and monoclonal DO-7 and PAb1801 antibodies. Results were compared to normal post-mortem pituitary tissue controls (n = 17). p53 protein accumulation was detected in invasive tumours (16%), but only in corticotrophinomas (2/4) and non-functional tumours (4/15). In non-invasive adenomas, protein accumulation was observed only in ACTH-secreting tumours where 50% were positive (16/32). No protein accumulation was identified in any control tissue. These results indicate that p53 protein accumulation may play a role in the development of Cushings adenomas and in the progression of non-functional tumours to the invasive state.

p53 Protein accumulates in Cushings adenomas and invasive non-functional adenomas.

The p53 protein, a negative regulator of cell growth, plays an important role in the pathogenesis of many human tumours following gene mutation and/or deletion. We screened a large number of sporadic pituitary tumours for p53 protein accumulation suggestive of gene mutation. Samples were divided into benign adenomas (n = 95) and invasive tumours with local or distant invasion (n = 26). All main tumour classes were represented. Putative p53 mutations were detected by immunohistochemistry on paraffin-embedded sections using polyclonal CM-1 and monoclonal DO-7 and PAb1801 antibodies. Results were compared to normal post-mortem pituitary tissue controls (n = 17). p53 protein accumulation was detected in invasive tumours (16%), but only in corticotrophinomas (2/4) and non-functional tumours (4/15). In non-invasive adenomas, protein accumulation was observed only in ACTH-secreting tumours where 50% were positive (16/32). No protein accumulation was identified in any control tissue. These results indicate that p53 protein accumulation may play a role in the development of Cushings adenomas and in the progression of non-functional tumours to the invasive state.