Linear performance characteristics of latissimus dorsi muscle: potential for cardiac assistance

Knowledge of the quantitative performance capabilities of skeletal muscle in a linear geometry is necessary to predict the performance and to optimize the design of linearly configured, skeletal muscle powered cardiac assist devices (MCADs). This study determined the performance characteristics of goat latissimus dorsi muscle (LDM) using a linear, ex vivo experimental apparatus. In five goats, the LDM (130.6 +/- 18.8 g) was dissected free of its distal attachments, connected to a series of weights (500 to 2250 g), and maximal tetanic contractions were elicited via thoracodorsal nerve stimulation. Second order polynomial equations were derived to represent each of the following variables versus load: muscle prestretch (range 1.5 to 5.4 cm), contraction duration (220 to 360 milliseconds), contraction shortening distance (13.5 to 10.9 cm), contraction velocity (60 to 31 cm/s), generated stroke power (3 to 7 W), and stroke work (0.7 to 2.4 J). Analysis of the potential stroke volumes obtained with a linearly configured, cylindrically shaped MCAD directly coupled to the circulation indicate that a feasible MCAD operating region exists based on the LDM performance data across a range of device geometries and mean ejection pressures.     

The effect of RG 12525 on leukotriene D4-mediated pulmonary responses in guinea pigs

RG 12525 (5-(2-[4-quinolin-2-yl)methoxy] phenoxymethyl)benzyl tetrazole) is under investigation as a specific inhibitor of leukotriene D₄ (LTD₄). The present studies examine the effect of orally administered RG 12525 on LTD₄ mediated pulmonary responses in three separate guinea pig models. The compound inhibited antigen-induced mortality in the systemic anaphylaxis model with an ED₅₀ (95% confidence interval)=2.2 (0.8–6.4) mg/kg. In this model, the activity half-life of RG 12525 was shown to be 6.5 hours and the compound offered significant protection within 15 minutes of administration. RG 12525 also protected against LTD₄-induced bronchoconstriction in a model measuring changes in pulmonary function with an ED₅₀=0.6 (0.4–1.0) mg/kg. The same level of activity was observed in a similar model which monitored changes in pulmonary function in response to exogenous antigen in actively-sensitized guinea pigs. Together, these data indicate that RG 12525 is a potent, orally active LTD₄ antagonist which possesses the requisite profile for potential clinical development.     

The Personality Research Form as a therapy outcome measure of social behavior

Reported two studies that examined the efficacy of the Personality Research Form (PRF) as an outcome measure for interventions designed to increase social competence. In the first study (N = 83), the degree to which PRF scales can predict criteria frequently used in social skills training outcome research was examined, and the PRF was shown to be sensitive to such criteria. The second study (N = 24) assessed the relative degree to which the PRF scales and more frequently used outcome measures, including the above criteria, are affected by factors non-specific to social skills training interventions (suggestion for improvement). While three PRF scales were affected significantly, demand effects were much more pervasive on the other measures, which suggests that those measures can be used to obtain valid estimates of treatment effects only when experimental control of non-specific effects is possible. Two PRF scales, Affiliation and Exhibition, were shown to be both sensitive to criteria and resistant to demand effects, and as such may be useful as outcome measures in non-controlled clinical settings.     

Pulmonary carcinoid tumours: a comparative regional study.

Twenty-two pulmonary carcinoid tumours (18 central, 4 peripheral) were seen in this department over an 11-year period. The majority of the tumours displayed a mixed pattern on microscopic examination, and cell-nest formation was a prominent feature in sixteen. The findings are at variance with the results of a similar series reported from Japan and suggest that there is regional variation in the tumour pattern of pulmonary carcinoids. Various aspects of the histopathology are discussed, and a causal relationship between ossification of bronchial cartilage in these tumours and locally produced calcitonin is postulated.     

The association of particular types of Proteus with chronic suppurative otitis media

During a period of 12 months, 57 strains of Proteus were isolated from the ears of 38 unrelated patients with chronic suppurative otitis media. Each strain was identified, typed for bacteriocin production and sensitivity, and tested for Dienes compatibility. The majority of the strains (79%) were P. mirabilis; all but one of the remainder were P.vulgaris. Although 19 different bacteriocin production/sensitivity types were found, two rare types, P. mirabilis P7/S5,12 and P. vulgaris P0/S9, were associated with 47% of these infections. This was confirmed by Dienes typing. Patients with bilateral ear disease carried a different strain in each ear. There was no evidence that persistence of infection had arisen because of the development of antibiotic resistance. Although there was some evidence that persistence may have been the result of reinfection, the isolation of these rare types of Proteus from so many patients with chronic suppurative otitis media may indicate that they play an important role in the pathogenesis of the disease. Most of the Proteus isolates were of "non-faecal" types and it is believed that infection had arisen by a route other than the faecal-aural one.     

Cellular localisation of HHV-8 in Castleman's disease: is there a link with lymph node vascularity?

AIMS: Human herpesvirus 8 (HHV-8) has been identified in multicentric Castleman's disease and in angioimmunoblastic lymphadenopathies. However, the presence of the virus does not necessarily indicate an aetiological role in these conditions. This study investigates the cell types infected by HHV-8 in Castleman's disease and examines the correlation between HHV-8 and Castleman's disease lymph node angiogenesis. METHODS: Sixteen formalin fixed, paraffin wax embedded samples from patients with Castleman's disease (six multicentric, 10 solitary) were examined for the presence of HHV-8 using the polymerase chain reaction (PCR), non-isotopic in situ hybridisation, PCR in situ hybridisation (PCR-ISH), and real time quantitative TaqMan PCR to HHV-8 open reading frame 26 (ORF-26), and viral (v)-cyclin encoding regions. Vascularity was assessed using CD34, CD31, and factor VIII immunocytochemistry, and lymph nodes were scored as "low" or "high". RESULTS: Five multicentric Castleman's disease and two solitary Castleman's disease biopsies were positive for HHV-8. HHV-8 was identified in approximately 10% of intranodal B lymphocytes, in endothelial cells, and in subcapsular spindle cell proliferations. The copy number of HHV-8 was low at 10-50 copies/1000 cells. The highest copy number was in subcapsular spindle cells. There was no correlation between vascularity score and HHV-8 status. CONCLUSION: The preferential localisation of HHV-8 in subcapsular spindle cell proliferations (where early intranodal Kaposi's sarcoma initiates) and endothelial cells in Castleman's disease might finally explain the link between intranodal Kaposi's sarcoma and Castleman's disease.     

The yeast type II myosin heavy chain: Analysis of its predicted polypeptide sequence

Summary We have completed the nucleotide sequence of the yeastMYO1 gene and deduced its amino acid sequence. The gene is 5553 bp long and contains no introns. Analysis of the sequence, as well as its comparison with other myosins, demonstrate that the yeast protein is a type II myosin heavy chain with characteristic head and tail regions. The latter domain contains six proline residues in two clusters of three, at approximately two thirds from the start of the gene.     

Evidence for sympathetic neural influence on human corneal epithelial function

Patients with unilateral Horner's syndrome were studied to determine the influence of sympathetic innervation on the structure and function of the human cornea. There was no difference in total corneal thickness, corneal oxygen uptake rate or corneal touch threshold between the normal and Horner's eyes of these patients. Epithelial thickness, however, was slightly but significantly greater in the Horner's eye than in the normal fellow eye (P less than 0.025). When subjected to a hypoxic "Stress Test", patients with post-ganglionic lesions showed significantly more epithelial greying and microcystic oedema (P less than 0.025 and P less than 0.01, respectively) and reported seeing smaller and brighter haloes in the Horner's eye. The cornea of the affected eye of these patients also showed a significantly shower rate of deswelling in the first hour following the "Stress Test" (P less than 0.05). These findings suggest that both in the resting state and when the cornea is physiologically challenged, the sympathetic nervous system and in particular, the terminal sympathetic neuron, has a small but significant influence on the human corneal epithelium.