Prevalence and some clinical characteristics of equine cheek teeth diastemata in 471 horses examined in a UK first-opinion equine practice (2008 to 2009).

Cheek teeth (CT) diastemata are now recognised as a clinically significant equine disorder, but their prevalence in the general equine population is unknown. There is also limited information on the signalment of affected horses; the more commonly affected Triadan sites; and the shape and clinical characteristics of CT diastemata. During the 12-month study period (2008 to 2009), standardised records were obtained during routine dental examinations performed by five veterinarians in a first-opinion equine practice. Cheek teeth diastemata were identified in 49.9 per cent of all horses (n=471) of mean age 11 years (range one to 30 years), with 83.5 per cent of all diastemata affecting mandibular CT and 16.5 per cent affecting maxillary CT. The mean number of diastemata per case was 1.7 (range one to 20) and the mandibular 07 to 08 position was most commonly affected. Valve diastemata were more common (72.1 per cent prevalence) than open diastemata (27.9 per cent). Food trapping was present in 91.4 per cent of diastemata, with gingivitis and periodontal pockets adjacent to 34.2 per cent and 43.7 per cent, respectively. Halitosis was present in 45.5 per cent of affected horses. There was an age-related increase in both the prevalence of diastemata, and in the numbers of diastemata per affected horse, and horses over 15 years old had a significantly increased proportion of open diastemata.

Characterization of a 20 kDa DNase elicitor from Fusarium solani f. sp. phaseoli and its expression at the onset of induced resistance in Pisum sativum.

Summary DNase released from Fusarium solani f. sp. phaseoli (Fsph DNase) has previously been reported to induce pathogenesis-related (PR) genes, phytoalexin accumulation and disease resistance against subsequent challenge with the true pea pathogen, Fusarium solani f. sp. pisi (Fspi). This report is a further analysis of DNase production with probes specific for both the gene and protein. N-terminal analysis of the approximately 20 kDa Fsph DNase protein facilitated both the development of anti-Fsph DNase antiserum and the cloning of the Fsph DNase gene. Utilizing the anti-Fsph DNase antiserum to prepare an affinity column, we demonstrated that the retention and recovery of the DNase activity was associated with this protein. Fsph DNase protein was detectable by Western analysis in both the fungi and plant cytoplasm within 6-8 h following inoculation of the pea endocarp surface. Partially purified DNase detected via catalytic activity began accumulating within pea tissue at 3 h post-inoculation. Enhanced fragmentation of pea DNA occurred within 5 h following treatment of pods with Fsph DNase or inoculations with the two fungi. DNA cleavage within the nuclei of endocarp pea cells was detectable via a TUNEL assay at 3 h post-inoculation. As a result of these findings, we propose that the entrance of Fsph DNase into the pea cell and the signalling of plant defence responses is temporally associated with the damage of host DNA.

Light-regulated and organ-specific expression of types 1, 2, and 3 light-harvesting complex b mRNAs in Ginkgo biloba.

In a prior study (E. Chinn and J. Silverthorne [1993] Plant Physiol 103: 727-732) we showed that the gymnosperm Ginkgo biloba was completely dependent on light for chlorophyll synthesis and chloroplast development and that expression of light-harvesting complex b (Lhcb) mRNAs was substantially increased by light. However, dark-grown seedlings that were transferred to constant white light took significantly longer than angiosperm seedlings to initiate a program of photomorphogenesis and the stems failed to green completely. We have prepared type-specific probes for mRNAs encoding major polypeptides of light-harvesting complex II (Lhcb1, Lhcb2, and Lhcb3) and have used these to analyze the expression of individual Lhcb mRNAs during greening. All three sequences accumulated in the top portions of dark-grown seedlings transferred to light, but, as was seen previously for total Lhcb mRNAs, there was a transient, reproducible decline in the levels of all three mRNAs after 4 d in the light. This transient decrease in Lhcb mRNA levels was not paralleled by a decrease in Chl accumulation. By contrast, there were significantly lower levels of all three Lhcb mRNAs in the lower portions of greening dark-grown stems as well as lower Chl levels. We conclude that although the tops of the plants have the capacity to etiolate and green, Gingko seedling stems continue a program of development into woody tissue in darkness that precludes greening when the seedlings are transferred to the light.

Characteristics of rabbit muscle adenylate kinase inhibition by sulfur and recovery by dithiothreitol.

Structure-function relationships of rabbit muscle adenylate kinase (RMAK) were studied by examining the characteristics of inhibitions by hydrophobic inhibitors and reactivations by sulfhydryl reagents. RMAK is inhibited by 1-butanol,N-ethylmaleimide (NEM) and elemental sulfur (S8) with increasing effectiveness in the order of increasing hydrophobicity. Characteristics of these hydrophobic inhibitors are compared with inhibitors forming covalent bonds or reversible complexes. A mechanism is proposed for hydrophobic inhibitors of RMAK that involves conformational changes promoted by interacting with hydrophobic regions. The reversal of RMAK inhibition by sulfhydryl compounds involves a conformational change that exposes hydrophobic regions and the inhibitor to water. Circular dichroism (CD) data show changes in the secondary structures of RMAK, indicating that the inhibitors and the sulfhydryl compounds promote conformational changes. The results of these studies show that the activity of a small enzyme can be controlled in a manner analogous to the allosteric control of larger enzymes.

Light-dependent chloroplast development and expression of a light-harvesting chlorophyll a/b-binding protein gene in the gymnosperm Ginkgo biloba.

Unlike conifers, the gymnosperm Ginkgo biloba is dependent on light for chlorophyll (Chl) synthesis and initiation of chloroplast development. Dark-grown seedlings show complete etiolation, including no detectable Chl accumulation, no leaf expansion, and increased hypocotyl elongation. When dark-grown seedlings are placed in white light, Chl synthesis and leaf expansion are initiated, but unlike angiosperms, which initiate rapid photomorphogenesis, Ginkgo takes at least 1 week to change to a normal light-regulated pattern of growth. A cDNA clone (pLhcb*Gb1) encoding a Chl a/b-binding protein of light-harvesting complex II from Ginkgo mRNA has been used as a probe for the expression of this family of mRNAs. We have found that, in common with angiosperms but in marked contrast to pines, Lhcb mRNA is expressed in a highly light-dependent manner. In addition to being expressed in light-grown leaves, this sequence is also expressed in the green tissues of immature seeds. The Lhcb mRNA appears during greening in parallel with the onset of Chl synthesis. The complete sequence of pLhcb*Gb1 has been determined and the deduced amino acid sequence was found to be of type I based on comparison with signature sequences of angiosperm and gymnosperm sequences.

Continuous passive motion following partial ankle joint arthroplasty.

Retrospective preliminary report of 19 cases undergoing partial ankle joint arthroplasties with open surgical procedures were rehabilitated with continuous passive motion (CPM). Preoperative and post-operative ankle range of motion and subjective findings (pain, physical signs, activity, quality of motion) were evaluated. Results indicated significant increases to ankle joint range of motion with the use of continuous passive motion, decreased pain, increased activity, decreased edema, and improved quality of motion in the majority of patients undergoing ankle joint arthroplasty with continuous passive motion.

Evidence for conformers of rabbit muscle adenylate kinase.

Changes of the apparent Mr values and the circular dichroism patterns suggest the existence of three relatively stable conformers of rabbit muscle adenylate kinase (RMAK). The effects of dithiothreitol (DTT) which stimulates activity, pH, the substrates, and ATP on the Mr value and the Stokes radius of RMAK were determined from gel filtration data, and apparent Mr values near 22,000, 26,000, and 29,000 resulted. Substrates generated multiple Mr values, suggesting the presence of multiple conformers of RMAK. The higher apparent Mr values were obtained in the presence of DTT and at the higher substrate concentrations, indicating more open conformations. The effect of the substrates on the conformation of RMAK is discussed in relation to the kinetic mechanism of this random bireactant system. Circular dichroism studies were undertaken in order to observe any changes in the secondary structures of RMAK in relation to changes of the Mr values. The secondary structure composition of RMAK, determined under our conditions, does not agree with results determined from crystallographic studies. The gel filtration and the CD studies suggest that above pH 7 a more open conformation of RMAK obtains in the presence of DTT. The results of these studies are discussed with reference to the location of the active sites.

Pigmented spindle cell nevus. Clinical and histologic review of 90 cases.

A clinical and histologic review of 90 patients with melanocytic lesions termed pigmented spindle cell nevi (PSCN) is reported. The lesions are small in surface diameter, sharply confined both clinically and histologically, and often occur on the proximal extremities of young adults. They are generally of recent onset, moderately to heavily pigmented, and made up of nests of spindled cells confined to the epidermis and papillary dermis. There were 30 male and 60 female patients. Their average age was 25.3 years (ranging from 2.5 to 56 years). Lesions were located on the extremities in 61 cases (67%). Follow-up was possible in 38 cases seen more than 6 months after histologic diagnosis and ranged up to 40 months (average 14 months). No local recurrence or distant spread was found. The importance of recognizing this lesion lies in differentiating it from malignant melanoma. Conservative but complete excision has resulted in no recorded instances of local recurrence or distant spread.

Hematologic manifestations in homosexual men with Kaposi's sarcoma.

Peripheral blood and bone marrow findings are presented for six homosexual males with Kaposi's sarcoma. Cytopenia in one or more cell lines was common in this group of patients, including two individuals with pancytopenia. Bone marrow findings in all patients, while not specific, were similar in that adequate numbers of normal appearing erythroid, myeloid, and megakaryocytic elements were present. Mild plasmacytosis as well as reticulin fiber increase were common findings. No patient, at time of study, demonstrated marrow involvement with Kaposi's sarcoma. We conclude that depression of peripheral blood counts in these patients was not due to marrow underproduction, and discuss possible mechanisms for increased blood cell destruction.

Acinic cell carcinoma: a clinicopathologic study of thirty-five cases.

A clinicopathologic study of 35 cases of acinic cell carcinomas is presented. Complete follow-up information was available on 31 patients (average period, 7-5 years). The malignant potential of these neoplasms is affirmed by observations that metastases (local and distant) occurred in nine patients and that eight patients died as a consequence of their carcinoma. Retrospective classification of the carcinomas into high and low grade lesions correlated well with ultimate biologic behavior but is unlikely to be successful in an intra-operative (frozen section) mode. This limitation is due to: (a) sampling limitations at the time of primary surgery and (b) the malignant behavior of the occasional low grade carcinoma. Histologic features characterizing high grade carcinomas are local aggressive infiltration and areas of the tumor that appear analogous to the embryonic and post-embryonic terminal tubules and intercalated ducts. The best opportunity for cure of these neoplasms lies in their complete surgical removal at the time of initial treatment. For this, a total parotidectomy is the procedure of choice. Enucleation and local excision is to be condemned.

The pathology of head and neck tumors: salivary glands, part 2.

Acinic-cell carcinomas and mucoepidermoid carcinomas remain somewhat controversial salivary-gland lesions. Because of an ambiguity in the literature concerning their malignant potential and a lack of sufficient follow-up periods, these carcinomas have been underestimated with respect to their morbidity and lethality. The failure of histopathologic evaluation to successfully predict the subsequent biologic course of these neoplasms should not mitigate treatment. Acinic-cell carcinomas are usually isomorphic neoplasms having their genesis in the neoplastic reserve cells of the terminal portions of the duct system. Mucoepidermoid carcinomas, on the other hand, may be described as forming a histologic spectrum or continuum from the most highly differentiated to the most poorly differentiated malignancy. They arise from the interlobular and intralobular ducts. The histopathologic features of these two neoplasms are presented, along with a review of their biologic activity in humans.

Serum creatinine. A CAP survey.

The results of the 1976--1977 College of American Pathologists Survey of serum creatinine measurements performed by more than 5,000 laboratories are presented. The most widely used method employs the colorimetric measurement of the alkaline picrate-creatinine (Jaffe) reaction. In general, all manual and automated systems yielded comparable creatinine concentrations except the centrifugal analyzers, which manifested a consistently high bias. Interlaboratory variation was lowest for continuous-flow and the DuPont discrete systems. Lloyd's reagent resulted in a clinically insignificant reduction of creatinine concentration in lyophilized sera.