Benzo(a)pyrene activates L1Md retrotransposon and inhibits DNA repair in vascular smooth muscle cells

Benzo(a)pyrene (BaP) modulates vascular smooth muscle cells (vSMCs) from a quiescent to proliferative phenotype, a shift associated with activation of L1Md retrotransposon [K.P. Lu, K.S. Ramos, Biochem. Biophys. Res. Commun. 253 (1998) 828-833]. The present studies were conducted to evaluate L1Md activation profiles in murine vSMCs treated with BaP or its oxidative metabolites, and to screen for possible insertional mutations into p53 and retinoblastoma (RB) genes. We also sought to examine the profile of DNA damage and repair in BaP-treated vSMCs. Northern analysis revealed that BaP (0. 03-3microM), and its major reactive 7,8-diol metabolite (0. 03-3microM), activate L1Md gene in a concentration-dependent manner. Two other metabolites, 3-OH BaP and 3,6-BaP quinone (0.03-3microM), as well as hydrogen peroxide (25-75microM) also activated L1Md. No insertional mutations into either p53 or RB genes were observed in vSMCs treated with BaP in vitro, although a slight elevation of p53 mRNA was observed as early as 4h after chemical challenge. Treatment of vSMCs with 3 or 30microM BaP for 4h increased unscheduled DNA synthesis (UDS) 1.4- and 2.5-fold, respectively. Challenge with 0. 3microM BaP for 24h inhibited DNA repair capacity in vSMCs for up to 48h. These results demonstrate that BaP and its oxidative metabolites activate L1Md retrotransposon in vSMCs, which coupled to DNA damage and inhibition of DNA repair are part of the atherogenic response elicited by BaP and related hydrocarbons.

Human colon cancer cells express multiple glycoprotein ligands for E-selectin

The interaction between the colon tumor cell surface and the endothelial cell layer is an important component of tumor intravasation, extravasation, and metastasis. Multiple studies suggest that tumor cells may bind to E-selectin expressed on endothelial cells during these processes. To identify possible E-selectin ligands on tumor cells that may participate in this mechanism, we used E-selectin-Ig chimera affinity chromatography to isolate glycoproteins from the human colon cancer cell line Colo-205. Binding of these cells to E-selectin was specific, required the presence of calcium, and could be blocked by antibodies against E-selectin. We identified LAMP-1 (lysosomal membrane glycoprotein-1), LAMP-2, and two high molecular weight glycoproteins (>400 kDa and 300 kDa) as the main E-selectin ligands on Colo-205 cells. Treatment of the cells with N-glycanase and O-sialoglycoprotease abolished their binding to E-selectin. The high MW glycoproteins contained sialyl Lewis X and/or sialyl Lewis A glycoconjugates, and appeared to be either alternatively spliced or alternatively glycosylated forms of MUC-1 (mucin-1).

Different patterns of angiogenesis in sarcomas and carcinomas

Solid tumors depend on angiogenesis for growth and metastasis. It has been shown that blood vessel density, as determined by counting the number of capillaries in clustered bursts, is a significant prognostic factor in carcinomas. It is unclear, however, whether vessel density is a prognostic factor in sarcomas. In this study, we examined angiogenesis in sarcomas of various grades and compared their vascular patterns to those of carcinomas. Microvessels were identified by von Willebrand factor staining. The matrix of multiple sarcoma and breast carcinoma specimens were extracted and subjected to Western analysis of various angiogenic factors and inhibitors. Metalloproteinase inhibitor presence was also determined by in situ hybridization. In breast carcinomas, capillaries were clustered in bursts within the stroma of the tumor, whereas the sarcoma capillaries were homogeneously distributed in the tumor stroma. Random blood vessel density per high power field in sarcomas did not correlate with patient prognosis. The matrix of sarcomas and carcinomas contained both angiogenic stimulators and inhibitors. Tissue inhibitor of metalloproteinase-1 was found predominantly in fibroblasts and myofibroblasts in the matrix of carcinoma specimens. The difference in the pattern of angiogenesis in sarcomas and carcinomas may be attributable to the presence of fibroblasts and myofibroblasts in carcinomas, resulting in the compartmentalization of bursts of angiogenic factors. The homogeneous appearance of vessel density in sarcomas observed in the present study would be the consequence of the influence of a single compartment.

Arthroscopic subacromial decompression: responsiveness of disease-specific and health-related quality of life outcome measures

Twenty-eight patients who presented with stage II or early stage III impingement syndrome were evaluated before and after decompression surgery to examine the sensitivity and responsiveness of health-related quality of life and disease-specific measures. The outcome instruments used included the Medical Outcomes Study SF36 health survey; the Constant-Murley shoulder scoring system (CM), the University of California at Los Angeles shoulder rating scale (UCLA) and visual analogue scales (VAS) for pain. Preoperative and short-term postoperative evaluations showed significant improvements in all outcome instruments, including pain and physical role dimensions of the SF36. However, the UCLA and VAS pain scores were confirmed as the most responsive and sensitive measures to short-term change following arthroscopic decompression.

Interstitial pneumonitis following mitozantrone, chlorambucil and prednisolone (MCP) chemotherapy

We describe two cases of interstitial lung disease in patients with non-Hodgkin's lymphoma who were treated with combination chemotherapy including mitozantrone. In both we had radiological and histological evidence of interstitial lung disease, with patterns of organizing pneumonia and hypersensitivity without a clear aetiological agent. Clinical resolution occurred on withdrawal of chemotherapy. One patient required a course of corticosteroid treatment. To date, both patients are well and in remission, and there has been no recurrence of their respiratory disease. We postulate that these observations are hitherto undescribed pulmonary abnormalities secondary to mitozantrone therapy.

Taking a sexual history

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An audit of 267 consecutively excised mammographically detected breast lesions 1989-1993

Pathology reports and slides were reviewed from 267 mammographically detected impalpable breast lesions, excised after hookwire localisation. There were 182 benign and 85 malignant lesions (benign to malignant ratio of 2.1:1). The invasive cancers tended to be small (mean 13 mm; 50% < or = 10 mm), of low histologic grade (38% Grade I), with a low incidence of lymph node metastases (15%). A high proportion of pure duct carcinoma in situ (DCIS) lesions (21%) was found, and an unusually high proportion of invasive lobular carcinoma (17%). Preoperative fine needle aspiration (FNA) was performed in 95 (36%) cases, including 47 (18%) sampled using sterotactic guidance and 48 (18%) sampled by palpation. The absolute sensitivity of diagnosis of malignancy was 32% and 5% respectively. In 79% of carcinomas further operation was performed, for axillary clearance or re-excision of incompletely excised tumor; this high rate was largely a result of a decision not to use frozen section diagnosis for impalpable lesions and because of the early stages of the development of preoperative needle diagnosis. 58% of invasive cancers, including seven of eight (87.5%) carcinomas with an extensive intraduct component (EIC + ve), and 72% of DCIS were incompletely excised at the first operation. Residual tumor was found in the re-excisions in 26% of EIC - ve invasive carcinomas, 71% of the EIC + ve cases and 56% of DCIS lesions. The malignant lesions had highly favourable prognostic indices. The need for concentration of experience with pre-operative FNA was highlighted. Positive excision margins were a good predictor for residual malignancy, particularly for EIC + ve cases and for DCIS lesions.

Surgical conditions of the cervical spine

This article reviews the four most common surgical conditions of the cervical spinal cord other than vertebral fractures including atlantoaxial instability, cervical disc disease, caudal cervical spondylomyelopathy, and spinal cord tumors. Each disease is reviewed by signalment, history, neurological examination, differential diagnosis, pertinent diagnostic testing, treatment, postoperative care, and prognosis.

Use of general practitioner beds in Leicestershire community hospitals

BACKGROUND

The shift in care from secondary to primary services is likely to place greater demands on community hospitals. Before changes in the provision of community hospitals can occur, baseline data are needed, outlining their current use.

AIM

A study was undertaken to obtain baseline data describing the use of general practitioner beds in Leicestershire community hospitals.

METHOD

A three-month prospective, observational study was carried out between February and May 1992 using data from a questionnaire completed by nurses and general practitioners and from patient hospital records. Study patients comprised all patients admitted to general practitioner beds in all eight Leicestershire community hospitals.

RESULTS

A 100% questionnaire response rate was obtained giving data on 685 hospital admissions. Around 70% of admissions were of patients aged 75 years and over. Of admissions, 35% were for acute care, 31% for respite care, 22% for rehabilitation, 7% for terminal/palliative care and 5% for other reasons. Fifteen per cent of patients had been transferred from a consultant bed. Of those not transferred, 91% were admitted by their usual general practitioner or practice partner and for 96% of these patients this was the general practitioner's first choice for care. There was significant variation in both the age mix and care category mix of patients between individual hospitals. Medical deterioration in an underlying condition and family pressure on the general practitioner or carers' inability to cope each contributed to around half of all admissions. Of all admissions, 38% lived alone, and 18% of carers were disabled. Incontinence was reported for 35% of patients, and 26% of all patients were of a high nursing dependency. There was low utilization of community services before admission and 33% received none. There was variation between individual hospitals in use of local and district general hospital investigations, specialist referral and types of therapy. Of 685 admissions 11% died during their stay. Of those discharged, 76% went to their own or a relative's home, 10% to a residential or nursing home and 9% were transferred to an acute bed. Nine percent of discharges were postponed and 10% were brought forward. On discharge to non-residential care, 26% of patients received no community services.

CONCLUSION

Shifting resources from secondary to primary care is a priority for purchasers. Both the introduction of the National Health Service and community care act 1990, and acute units having increasing incentives for earlier discharge, are likely to place greater demands on community hospital beds. Not all general practitioners have the option of community hospital beds. Before access to general practitioner beds can be broadened, existing beds should be used appropriately and shown to be cost-effective. Purchasers therefore require criteria for the appropriateness of admissions to general practitioner beds, and the results of a general practitioner bed cost-benefit analysis.

Pathology of canine bladder and urethral cancer and correlation with tumour progression and survival

Biopsy and necropsy specimens, comprising 107 primary carcinomas and three mesenchymal tumours, were reviewed from 110 dogs with cancer of the bladder, urethra, or both. Histological classifications developed for the assessment of human bladder cancer were found to be readily applicable to the dog. These classifications are based on histological features, including the pattern of growth, the cell type, the grade of transitional tumour and the depth of invasion of the bladder wall. Features associated with localized disease in canine transitional cell carcinoma included papillary architecture, "in-situ" tumour, low tumour grade and a strong peritumoral lymphoid cell reaction. Features of tumours with metastasis included infiltrating and non-papillary architecture, increasing tumour grade, depth of invasion, vascular invasion and presence of peritumoral fibrosing reaction. Wide variability was found within single tissue samples, indicating that multiple sample sites are necessary for the adequate characterization of a given lesion. Statistically significant correlations were found between: tumour grade and depth of invasion (P < 0.0001); tumour grade and presence of metastases (P < 0.029); and peritumoral desmoplasia and metastases (P < 0.029). It was concluded that canine bladder cancer could be classified for the purpose of clinical management with a modified World Health Organization system as developed for human tumours.

Canine bladder and urethral tumors: a retrospective study of 115 cases (1980-1985)

One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary Cooperative Oncology Group. Most tumors were malignant (97%) and of epithelial origin (97%). Lower urinary tract tumors were more common in older dogs weighing greater than 10 kg. The following significant (P less than 0.05) statistical associations were found using the University of Guelph hospital population as control; there was no sex predisposition although the female:male ratio was 1.95:1. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers, whereas German Shepherds were significantly under-represented among dogs with lower urinary tract tumors. These statistical associations should be interpreted cautiously because of possible demographic differences in hospital populations among the University of Guelph and other cooperating institutions. There were no significant correlations between age, gender, weight, breed, response to therapy, and survival time. Clinical signs were indicative of lower urinary tract disease and included hematuria, stranguria, and pollakiuria. The laboratory data were nonspecific except for urinalysis test results. Hematuria and inflammatory urinary sediments were most commonly reported; neoplastic cells were identified in the urine sediment of 30% of dogs with lower urinary tract tumors. Contrast cystography was a useful noninvasive diagnostic method since 96% of the dogs had a mass or filling defect in the lower urinary tract demonstrated by this technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of nitric oxide in nerve-mediated inhibition and action of vasoactive intestinal peptide in colonic smooth muscle

Neurally mediated relaxation of canine colonic smooth muscle is associated with an increase in the resting membrane potential and is blocked by inhibition of nitric oxide synthesis. N omega-nitro-L-arginine completely prevented nerve-mediated relaxation, an effect that was reversed by L-arginine but not D-arginine. Vasoactive intestinal peptide (VIP) also relaxed canine colonic smooth muscle. Part of this relaxation was due to activation of inhibitory nerves and this effect was mediated by nitric oxide. In addition to the neurally mediated effect, VIP affected smooth muscle directly. This relaxation was associated with a reduction of the plateau phase of the slow-wave type action potential, without an effect on the resting membrane potential. This action of VIP was similar to that of forskolin which suggests that VIP increases intracellular cyclic AMP. In summary, nitric oxide mediates inhibitory innervation to smooth muscle as well as activation of inhibitory nerves by VIP. The electrophysiological mechanism by which VIP directly affects smooth muscle is described, an effect not mediated by nitric oxide.

Complications of fractures repaired with casts and splints

Complications of external coaptation of fractures include delayed and nonunion healing from lack of adequate fracture stability, pressure and rub sores, leg swelling, dermatitis, joint laxity or stiffness, cast or splint breakage, and refracture. Most of the complications are a result of improper application of the coaptation device or poor management of the patient. Early recognition and treatment of complications are needed to minimize their effect. The number of complications resulting from external coaptation can be minimized by proper application of the cast or splint.

Analysis of rat lens 45Ca2+ fluxes: evidence for Na(+)-Ca2+ exchange

The influx and efflux kinetics of 45Ca2+ were studied in the rat lens in vitro. Both data sets could be fitted by a multi-compartment mathematical model and were interpreted in terms of extracellular, cytosolic and slowly-exchanging (bound) components. At the end of a 16-hr influx period, when uptake into the extracellular and cytosolic compartments is complete, the 45Ca2+ exchanged fraction is less than 20% of the total calcium determined by atomic absorption. The bound compartment is therefore by far the largest in the lens. The efflux rate constant determined from the model for the cytosolic compartment was approximately 8 x 10(-3) min-1 and its origin was confirmed by its sensitivity to temperature, absence of external sodium and presence of the amiloride-analogue, dichlorobenzamil. A 55% reduction in efflux was obtained in sodium-free solution, indicating that Na(+)-Ca2+ exchange is responsible for a large proportion of calcium movement from the lens against its electrochemical gradient. This was confirmed in influx studies where, reduction of the lens sodium gradient by either exposure to sodium-free medium or 0.1 mM ouabain significantly elevated the 45Ca2+ content of the lens relative to the control level. Exposure to sodium-free conditions also rendered the lens opaque, which did not occur in the absence of external calcium. These experiments suggest a critical role for Na(+)-Ca2+ exchange in maintaining a low internal Ca2+ and hence transparency.

Calcium-induced opacification and proteolysis in the intact rat lens

When intact rat lenses were incubated in artificial aqueous humor in the presence of 1 mM calcium and a sulfhydryl reagent p-chloromercuriphenyl sulfonate (pCMPS) a visible annular opacity developed within 4 hours. Combined photographic and ion-sensitive microelectrode investigations of the lenses demonstrated that the subsequent linear increase in opacification was accompanied by an increase in internal free calcium. Opacities were not observed in lenses incubated in the absence of either pCMPS or calcium. Gel electrophoresis of the soluble and urea-soluble fractions from lenses exposed to 1 mM calcium for periods of up to 14 hours showed no evidence for crystallin degradation and only minor proteolysis of cytoskeletal proteins. When lenses were incubated under identical conditions, but with 5 mM calcium, the degree of opacification increased up to approximately 8 hours and then remained constant. A progressive loss in cytoskeletal proteins was observed which correlated with a further increase in free calcium such that by 14 hours of incubation, when the internal calcium approached 1 mM, most of the spectrin and vimentin present in the cortex of the lens had disappeared. An unidentified 110-kilodalton protein also disappeared from lenses incubated in 5 mM calcium. These results indicate that proteolysis by calcium-dependent enzymes such as calpain may play a significant role in cytoskeletal regulation and metabolism in the lens. A role for cytoskeleton/membrane/crystallin interaction in calcium-induced opacification is discussed.

Ferritin is a translationally regulated heat shock protein of avian reticulocytes

Heat-shock avian reticulocytes exhibit enhanced synthesis of a greater than 450-kDa protein. Biochemical, immunochemical, and visual criteria were used to identify this protein as the iron storage protein ferritin. The 21-kDa ferritin subunits synthesized during heat shock are similar in size and pI to the subunits that are constitutively synthesized. The 2-6-fold heat shock-induced increase in ferritin synthesis appears to be regulated at the translational level as it is insensitive to actinomycin D. Northern and dot-blot hybridization analyses of cytoplasmic RNAs with avian H-ferritin cDNA fragments support the contention that the heat shock stimulation of ferritin synthesis is translationally regulated. These latter studies demonstrate that the heat shock-induced synthesis of ferritin does not involve a change in the amount of total cytoplasmic ferritin mRNAs, but rather appears to entail a translocation of cytoplasmic H-ferritin mRNAs from a polyribosome-free, translationally repressed state to a polyribosome-associated, translationally active state. These results suggest that thermally stressed avian reticulocytes have a critical and functional need for the synthesis of additional ferritin and that its enhanced synthesis, unlike the new and/or enhanced synthesis of the well-established avian heat shock proteins, is regulated wholly at the translational level.

Mammalian lens inter-fiber resistance is modulated by calcium and calmodulin

The relationship between Ca2+ and lens fiber cell communication was investigated in the isolated intact rat lens by using radiotracer and electrophysiological techniques. The lens internal calcium was increased by adding the SH oxidant diamide (1 mM), by incubating in a sodium-free (n-methylglucamine) solution or by increasing external calcium from 1 to 10 mM. A 12 hours incubation in diamide produced a ten-fold increase in 45Ca uptake into the lens which was accompanied by a ten-fold increase in internal resistance. Incubation in Na-free solution or in 10 mM Ca2+ both produced a 5-fold increase in 45Ca content, while the increase in internal resistance was five and six fold respectively. This uncoupling was prevented in the diamide and Na-free treated lenses by omitting Ca2+ from the incubation medium. Fiber cell uncoupling was noticed in each of these experimental conditions after approximately 5 hours incubation, and good recovery was obtained in the high calcium solution if the stress was removed. The calmodulin antagonists calmidazolium (3 microM) and W7 (100 microM) both prevented uncoupling in the high calcium solution, provided there was a 2 hours preincubation period in calcium-free solution containing antagonist before the stress was applied. These data indicate that lens fiber cell communication is required by Ca2+ and calmodulin.