Recurrent Twiddler's syndrome in a nonthoracotomy ICD system despite a Dacron pouch

Twiddler's syndrome is a highly recognized yet rare complication of pacemaker and cardioverter defibrillator (i.c.d.) implantation. We present a case in which persistent generator rotation resulted in lead dislodgment and inappropriate shocks in an initial ICD and recurrent lead fracture in a second ICD system. This case is unusual in that even with extensive surgical precautions including use of a Dacron pouch, generator rotation could not be prevented. Submuscular implantation and use of a smaller generator may prevent Twiddler's syndrome.

Is histological examination of tissue removed by general practitioners always necessary? Before and after comparison of detection rates of serious skin lesions

OBJECTIVES

To examine whether histological examination of all tissue removed by general practitioners in minor surgery increases the rate of detection of clinically important skin lesions, and to assess the impact of such a policy on pathologists' workload.

DESIGN

Before and after comparison.

SETTING

Stratified random sample of 257 general practitioner partnerships from the catchment areas of 19 English pathology laboratories.

SUBJECTS

Tissue removed in minor surgery by general practitioners during the control period (September 1992 to February 1993) and intervention period (September 1993 to February 1994).

INTERVENTION

General practitioners referred to their local pathology laboratory all solid tissue removed in all minor surgery, irrespective of their previous policy.

MAIN OUTCOME MEASURES

Numbers of specimens referred for histology by general practitioners during intervention and control periods; numbers of primary malignant melanomas, non-melanoma malignancies, premalignant lesions, and benign lesions.

RESULTS

257/330 partnerships participated (response rate 78%). During the intervention period 5723 specimens were sent, compared with 4430 during the control period. The referral rate increased by an estimated 1.34 specimens per 1000 patient years (95% confidence interval 0.93 to 1.76, P < 0.0001). General practitioners sent 204 specimens that were malignant (including 16 malignant melanomas) in the control period and 188 that were malignant (including 15 malignant melanomas) during the intervention period (change in total number of malignancies, -1.0 per 100,000 patient years (-5.9 to 3.8, non-significant).

CONCLUSIONS

The intervention was associated with a substantial increase in laboratory workload, all of which was accounted for by increases in non-serious lesions. This observation should be taken into account when considering the merits of a policy requiring histological examination in every case.

Fibroblast growth factor receptor signaling activates the human interstitial collagenase promoter via the bipartite Ets-AP1 element

Interstitial collagenases participate in the remodeling of skeletal matrix and are regulated by fibroblast growth factor (FGF). A 0.2-kb fragment of the proximal human interstitial collagenase [matrix metalloproteinase (MMP1)] promoter conveys 4- to 8-fold induction of a luciferase reporter in response to FGF2 in MC3T3-E1 osteoblasts. By 5'-deletion, this response maps to nucleotides -100 to -50 relative to the transcription initiation site. The 63- bp MMP1 promoter fragment -123 to -61 confers this FGF2 response on the rous sarcoma virus minimal promoter. Intact Ets and AP1 cognates in this element are both required for responsiveness. The AP1 site supports basal and FGF-inducible promoter activity. The intact Ets cognate represses basal transcriptional activity in both heterologous and native promoter contexts and is also required for FGF activation. FGF2 up-regulates a DNA-binding activity that recognizes the MMP1 AP1 cognate and contains immunoreactive Fra1 and c-Jun. Both constitutive and FGF-inducible DNA-binding activities are present in MC3T3-E1 cells that recognize the MMP1 Ets cognate; prototypic Ets transcriptional activators are not present in these complexes. Inhibitors of protein kinase C, phosphatidyl inositol 3-OH kinase, and calmodulin-dependent protein kinase do not attenuate MMP1 promoter activation. FGF2 activates ERK1/ERK2 signaling in osteoblasts; however, 25 microM MAPK-ERK kinase (MEK) inhibitor PD98059 (inhibits by > 85% the phosphorylation of ERK1/ERK2) has no effect on MMP1 promoter activation by FGF2. Ligand-activated and constitutively active FGF receptors initiate MMP1 induction. Dominant negative Ras abrogates MMP1 induction by constitutively active FGFR2-ROS, but dominant negative Rho and Rac do not inhibit induction. The mitogen-activated protein kinase (MAPK) phosphatase MKP2 [inactivates extracellular regulated kinase (ERK) = Jun N-terminal kinase (JNK) > p38 MAPK] completely abrogates MMP1 activation, whereas PAC1 (inactivates ERK = p38 > JNK) attenuates but does not completely prevent induction. Thus, a Ras- and MKP2-regulated MAPK pathway, independent of ERK1/ERK2 MAPK activity, mediates FGF2 transcriptional activation of MMP1 in MC3T3-E1 osteoblasts, converging upon the bipartite Ets-AP1 element. The DNA-protein interactions and signal cascades mediating FGF induction of the MMP1 promoter are distinct from two other recently described FGF response elements: the MMP1 promoter (-123 to -61) represents a third FGF-activated transcriptional unit.

The inhibition of colon-26 adenocarcinoma development and angiogenesis by topical diclofenac in 2.5% hyaluronan

Topical diclofenac in 2.5% hyaluronan inhibits basal cell carcinoma, actinic keratosis, and murine colon-26 growth in vivo. colon-26 tumor growth was preceded by angiogenesis and reduced apoptotic and mitotic indices. Diclofenac reduced proliferation and viability in vitro, and stimulated apoptosis. Hyaluronan inhibited proliferation and viability at 1 mg/ml but was inactive below this level. Topical application of diclofenac inhibited tumor prostaglandin synthesis and retarded angiogenesis and tumor growth (ratio of treatment:control, 0.174). The mitotic index remained unaltered in vivo, whereas the apoptotic index and necrosis were increased. Topical vehicle exhibited slight antitumor and antiangiogenesis activity. The substantial quantities of diclofenac delivered locally in hyaluronan may exhibit antitumor activity in similar fashion to those seen in vitro and explain its clinical efficacy.

Linkage between reovirus-induced apoptosis and inhibition of cellular DNA synthesis: role of the S1 and M2 genes

The mammalian reoviruses are capable of inhibiting cellular DNA synthesis and inducing apoptosis. Reovirus strains type 3 Abney (T3A) and type 3 Dearing (T3D) inhibit cellular DNA synthesis and induce apoptosis to a substantially greater extent than strain type 1 Lang (T1L). We used T1L x T3A and T1L x T3D reassortant viruses to identify viral genes associated with differences in the capacities of reovirus strains to elicit these cellular responses to viral infection. We found that the S1 and M2 genome segments determine differences in the capacities of both T1L x T3A and T1L x T3D reassortant viruses to inhibit cellular DNA synthesis and to induce apoptosis. These genes encode viral outer-capsid proteins that play important roles in viral attachment and disassembly. To extend these findings, we used field isolate strains of reovirus to determine whether the strain-specific differences in inhibition of cellular DNA synthesis and induction of apoptosis are also associated with viral serotype, a property determined by the S1 gene. In these experiments, type 3 field isolate strains were found to inhibit cellular DNA synthesis and to induce apoptosis to a greater extent than type 1 field isolate strains. Statistical analysis of these data indicate a significant correlation between the capacity of T1L x T3A and T1L x T3D reassortant viruses and field isolate strains to inhibit cellular DNA synthesis and to induce apoptosis. These findings suggest that reovirus-induced inhibition of cellular DNA synthesis and induction of apoptosis are linked and that both phenomena are induced by early steps in the viral replication cycle.

The role of vascular endothelial growth factor in a murine chronic granulomatous tissue air pouch model of angiogenesis

Chronic granulomatous inflammation may be considered an angiogenic-dependent process. Recently it has been demonstrated that vascular endothelial growth factor (VEGF) or vascular permeability factor is essential for tumour angiogenesis. Its role in inflammation-mediated angiogenesis has yet to be determined. In this study, the murine chronic granulomatous air pouch model was used to investigate the role of VEGF in angiogenesis. Animals were treated twice weekly with 10 micrograms per animal of neutralizing antibody to rh VEGF and the vascularity and granuloma dry weight were assessed after 7 days. This resulted in significant suppression of both angiogenesis and granuloma dry weight. Western blot analysis demonstrated the presence of VEGF; the levels of protein paralleled the angiogenic response. These results demonstrate for the first time that VEGF may be an important regulator of angiogenesis in inflammation.

Pentoxifylline does not delay bacterially induced preterm delivery in rabbits

OBJECTIVE

Our purpose was to determine whether pentoxifylline, a potent cytokine inhibitor, would delay bacterially induced preterm delivery in rabbits.

STUDY DESIGN

The study was a randomized, blinded, prospective trial. Twenty-seven rabbits underwent laparotomy. Of these, five (shams) received an intrauterine injection of endotoxin-free water, and the remaining 22 received an injection of 10(5) Escherichia coli into the lower uterine segment. Postoperatively the animals that received the Escherichia coli were divided into two groups. The placebo group (n = 11) received subcutaneous injections of saline solution three times a day and the treatment group (n = 11) received pentoxifylline 20 mg/kg/day in three divided doses. The following parameters were evaluated: (1) time until delivery, (2) time until death, and (3) intrauterine pathologic features.

RESULTS

All five of the sham rabbits were delivered at term without any evidence of infection. There were no differences in the preterm delivery rates between the placebo group (eight of 11) and the pentoxifylline-treated group (seven to 11). However, there was a trend toward prolonging time until death in the treatment group. There were no differences in intrauterine pathologic feature between the placebo and treatment groups.

CONCLUSION

Pentoxifylline does not delay Escherichia coli induced preterm delivery in rabbits.

Comparison of rehabilitation practice on hospital wards for stroke patients

BACKGROUND AND PURPOSE

The aim of the study was to observe patients on a stroke unit and to compare their activity with that of patients on conventional hospital wards to identify aspects of rehabilitation practice that might account for differences in outcome.

METHODS

Stroke patients admitted to the hospital were observed on three 8-hour shifts over 3 consecutive days. An observer recorded, at 10-minute intervals, where patients were, what they were doing, and whether their positioning was as recommended by rehabilitation therapists. Patients on a stroke unit were compared with those on conventional wards.

RESULTS

Stroke unit patients spent less time by their beds and more time in other locations on the ward (P < .001). There were significant differences in the frequency of behaviors observed in the two types of ward (P < .001). Stroke unit patients had significantly more interaction with nurses and therapists (P < .001). They were also more often in the recommended position (P < .001).

CONCLUSIONS

The proportion of time in therapeutic activity was low in all locations, with patients spending many hours sitting and doing nothing. Despite this, stroke unit patients had more therapeutic contact with staff and were more often in the recommended position. These two features may account for some of the differences in outcome.

Modulation by insulin of follicle-stimulating hormone and luteinizing hormone actions in human granulosa cells of normal and polycystic ovaries

Anovulation in polycystic ovary syndrome (PCOS) is associated with hyperinsulinemia and insulin resistance, but it has been unclear whether the ovary is insulin resistant in women with PCOS. The aims of this study were, firstly, to determine whether human granulosa cells respond to physiological concentrations of insulin and, secondly, to investigate insulin and gonadotropin interactions in vitro in granulosa cells obtained from normal (N) and polycystic ovaries (PCO). Granulosa cells were incubated with insulin with or without gonadotropins for 48 h. Insulin augmented not only basal production of estradiol and progesterone, but also LH-stimulated steroid accumulation in granulosa cell cultures from N and PCO. Insulin enhanced FSH-stimulated progesterone production by granulosa cells from N and PCO, but the effect on FSH-stimulated estradiol production was variable, ranging from no effect for granulosa cells from N to synergistic for granulosa cells from PCO of anovulatory subjects. Preincubation with insulin for 48 h increased subsequent basal and LH-induced, but not FSH-stimulated, steroid production. These data demonstrate that granulosa cells from PCO respond to insulin despite the association, in vivo, of PCOS with peripheral insulin resistance. Insulin preincubation enhances the subsequent response of human granulosa cells to LH. We propose that in anovulatory women with PCOS, elevated levels of insulin interacting with LH may contribute to the mechanism of anovulation.

Heme oxygenase: a novel target for the modulation of the inflammatory response

Chronic inflammatory diseases place a heavy social and economic burden on the resources of many nations, but the number of safe and effective treatments is limited. To date, the major research effort has concentrated on those mediators responsible for the initiation and maintenance of the pathological process. In contrast, little attention has been focused on endogenous factors responsible for the resolution of the inflammation. Heme oxygenase ((HO); EC 1.14.99.3) is the rate-limiting enzyme in the catabolism of heme to biliverdin (which is converted to bilirubin by biliverdin reductase), free iron and carbon monoxide (CO). Two isoforms of HO have been characterized, the constitutive isoform, HO-2, which is the major isoform present under physiological conditions, and the stress-induced isoform, HO-1, which has also been classified as heat-shock protein 32K (ref. 1). Increases in HO activity have been implicated in tissue protection against oxidative stress. In this communication, we describe the effects of modulating HO during an acute complement-dependent inflammatory response. Elevation of this enzyme resulted in a striking suppression, whereas inhibition of the enzyme led to a potentiation of the inflammatory response. Such novel enzyme modulation has application on the one hand to the treatment of inflammatory diseases and on the other hand to immnosuppressed states in which the impaired ability to mount an adequate inflammatory response may result in death from opportunistic infections.

Insulin action in human granulosa cells from normal and polycystic ovaries is mediated by the insulin receptor and not the type-I insulin-like growth factor receptor

In order to account for the effects of insulin on the polycystic ovary (PCO), despite peripheral insulin resistance in women with polycystic ovary syndrome (PCOS), it has been suggested that insulin may act through the type-I insulin-like growth factor (IGF) receptor and not the insulin receptor. We have tested this hypothesis by investigating the effect of anti-insulin receptor and anti-type-I IGF receptor antibodies on insulin-stimulated steroidogenesis in human granulosa cells in vitro from normal (N) and PCO. Insulin-stimulated estradiol and progesterone production was inhibited by an anti-insulin receptor antibody. In contrast, anti-type-I IGF receptor antibodies had no effect on insulin-stimulated steroidogenesis in granulosa cell cultures from N or PCO. Hence insulin acts via its own receptor in human granulosa cells from both N and PCO.

Polyarthritis in the rat: effects of tolerance and sensitization to the bacterial extract OM-89 with a possible mode of action

The Bacterial Extract OM-89 has been shown to significantly reduce paw swelling in an avridine-induced polyarthritis (AvPA) in female Wistar rats whether given orally for 3 weeks or as a series of i.p. injections. Paw swelling was also markedly reduced in groups of adult rats which had received i.p. injections of OM-89 as neonates. Three separate tolerance-inducing regimes were used and all were equally effective. It is suggested that OM-89 can modulate the undesirable immunological reactions to endogenous antigens and since oral administration has been shown to be clinically effective in the human, that the induction of oral tolerance could be a mechanism of action of OM-89.

Modulation of heme oxygenase activity in rat brain and spleen by inhibitors and donors of nitric oxide

The capacity of nitric oxide to activate or inhibit metalloprotein-containing enzymes underlies many of its biological actions. Heme oxygenase, involved in a variety of biological processes, does not contain heme but utilises it as a substrate. The substrate for nitric oxide, L-arginine (0.1-10mM), but not D-arginine, decreased heme oxygenase activity in rat brain homogenates. The arginine analogue L-NAME (0.1-10mM) increased activity in the same tissue. In spleen homogenates where endogenous nitric oxide activity is lower than in brain, these compounds had no effect. The nitric oxide donor sodium nitroprusside (0.001mM-10mM) reduced heme oxygenase activity in both brain and spleen. These results suggest that biological effects attributed to modulation of nitric oxide synthase may act via heme oxygenase.

Expression and modulatory effects of heme oxygenase in acute inflammation in the rat

Heme oxygenase (HO) is the rate limiting enzyme in the catabolism of heme molecules to the bile pigments which have recently been demonstrated to be strong antioxidants. In this study we analyzed the activity of HO in inflammatory cells isolated from a model of carrageenin induced acute inflammation in the rat. HO activity was significantly higher 24 hours after induction of the inflammation, this increase in activity coincided with the appearance of the highly inducible isoform of HO, Heat Shock Protein 32 kDa (HSP32) as detected by Western Blot analysis. Pre-treatment of animals with Tin protoporphyrin, a HO inhibitor, increased cell exudate at 24 hour in this model by 128% as compared to vehicle control. In comparison pre-treatment with a HO inducer, Ferriprotoporphyrin, decreased inflammatory cell number by 50% and cell exudate by 73% at 24 hours compared to control. These results suggest that HO may represent an endogenous protective mechanism against free radicals in acute inflammation and may be involved in the resolution of acute inflammation. The HSP32 isoform of HO may therefore represent a novel therapeutic target for the modulation of the inflammatory response.

OM-89 modulation of chronic inflammation: relevance to clinical use

The modulatory effects of a glycoprotein-rich endotoxin-free extract of Escherichia coli (OM-89) have been studied using the cotton pellet model of chronic inflammation in the male Wistar rat. OM-89 had a suppressive effect on the size of granuloma surrounding implanted cotton pellets at both 4 and 40 mg/kg given three times weekly. The lower dosage of 4 mg was effective throughout and there was little to be gained by increasing the dose as further reduction of granuloma size was not obtained. Whether given prior to, at the same time as, or after an inflammatory stimulus, OM-89 had suppressive effects. However, if given before, animals at first went through a phase of 'sensitization' before suppressive effects were seen on further exposure to OM-89 antigens, a phenomenon which might have bearing on clinical findings in rheumatoid arthritis. In animals presensitized to a cotton pellet, OM-89 was statistically as effective as indomethacin in suppressing a second granuloma. OM-89 combined with indomethacin showed additive effects and was highly effective. The results indicate that OM-89 could be efficacious in the treatment of chronic inflammatory conditions and there is the possibility that in appropriate circumstances OM-89 might replace some drugs currently used and in others reduce their dosage.

Coronary vasoconstriction in vitro in the hearts of polyarthritic rats: effectiveness of in vivo treatment with the endothelin receptor antagonist SB 209670

Here we demonstrate that perfused hearts removed from polyarthritic rats develop a pronounced coronary vasoconstriction ex vivo. This vasoconstriction is almost entirely blocked by in vivo pretreatment of the rats with the endothelin receptor antagonist, SB 209670. Thus, inflammatory states may be associated with an increased activity of the endothelin system, leading to vascular dysfunction and vasoconstriction.

Cyclo-oxygenase and nitric oxide synthase isoforms in rat carrageenin-induced pleurisy

1. The profiles of cyclo-oxygenase (COX) and nitric oxide synthase (NOS) isoforms were determined in the rat carrageenin-induced pleurisy model of acute inflammation. 2. The enzymes were assessed in peripheral blood leucocyte (PBL) cell pellets taken from untreated animals and at 2, 6 and 24 h after injection of the irritant in pleural exudate cell pellets and lung homogenates. 3. COX activity was assessed by the generation of prostacyclin (PGI2, measured as the stable metabolite, 6-keto prostaglandin F1 alpha) and prostaglandin E2 (PGE2). Western blot analysis and immunohistochemistry were also carried out. 4. NOS activity was based on the conversion of [3H]-L-arginine to [3H]-L-citrulline in the presence (total NOS activity) or absence of Ca2+ (inducible NOS; iNOS). 5. Peripheral blood leucocyte samples contained low levels of COX activity. In pleural exudate cell pellets, COX activity peaked at 2 to 6 h after injection of the carrageenin. At 24 h, COX activity was significantly reduced. 6. Western blot analysis demonstrated that the inducible isoform of COX (COX-2), was the predominant enzyme at all time points. Low levels of COX-2 were seen in PBLs. In pleural exudate cell pellets maximal COX-2 protein levels were seen at 2 h. 7. Immunohistochemistry confirmed the findings of Western blot studies. Approximately 10% of polymorphonuclear neutrophils (PMNs) in PBLs from untreated animals were immunopositive for COX-2. In cell pellet smears from carrageenin-induced pleurisy taken 2 h after injection of the irritant, PMNs were also the major source of COX-2 immunoreactivity. A small proportion of macrophages and mesothelial cells were also immunolabelled for COX-2.8. Low levels of NOS activity were seen in PBLs. In pleural exudates NOS activity was maximum at 6 h and greatly reduced by 24 h. This activity was solely attributable to iNOS.9. The present results illustrated a similar profile of COX and NOS activity in the carrageenin-induced pleurisy model of acute inflammation. It was demonstrated that COX-2 and iNOS were the predominant isoforms of their respective enzymes.

The relationship of insulin insensitivity to menstrual pattern in women with hyperandrogenism and polycystic ovaries

OBJECTIVE

Insulin insensitivity is a recognized feature of polycystic ovary syndrome (PCOS) but previous studies have suggested that circulating insulin concentrations are normal in hyperandrogenaemic women with regular cycles. The aim of this study was to examine the relationship between insulin sensitivity and menstrual pattern in women with PCO.

DESIGN

A cross-sectional study of insulin sensitivity in a cohort of PCO subjects with oligomenorrhoea compared to women with PCO and regular menstrual cycles and a group of normal control subjects.

SUBJECTS

Seventy-two women with polycystic ovaries on ultrasonography were studied. PCO subjects had clinical and/or biochemical evidence of hyperandrogenism; 53 had oligo/amenorrhoea (olig) and 19 had regular menses (reg). Results were compared with 31 control subjects. The groups were matched for age, weight and ethnic origin.

METHODS

Glucose and insulin responses to 75 g oral glucose were measured. Insulin sensitivity was assessed by the decline in plasma glucose following intravenous insulin (0.05 U/kg).

RESULTS

Glucose area (mean +/- SEM) after oral glucose was increased slightly in both PCO groups compared with controls (olig 37.6 +/- 1.4, reg 36.0 +/- 1.8, control 33.7 +/- 0.9 mmol/l h, both P < 0.01). Insulin area median (interquartile range) in response to glucose was significantly greater in the oligomenorrhoeic group (346 (239-734) mU/l h), compared with both PCO with regular cycles (246 (148-355), P < 0.01) and controls (221 (147-277), P < 0.01). Insulin sensitivity was reduced (P < 0.01) in the oligomenorrhoeic group (147 +/- 9.2 mumol/l min) compared to controls (185 +/- 7.4) but was normal in PCO with regular cycles (182 +/- 12.5). Insulin sensitivity did not correlate significantly with plasma testosterone or with SHBG levels, but plasma insulin concentrations correlated negatively with SHBG levels (fasting insulin vs SHBG, r = -0.47, P < 0.01; insulin area vs SHBG, r = -0.41, P < 0.01).

CONCLUSIONS

Insulin insensitivity in polycystic ovary syndrome occurs when there is oligo/amenorrhoea but not when the menstrual cycle is regular. This is consistent with PCO and insulin insensitivity being separate abnormalities which when combined are associated with anovulation.

Inhibitory effects of insulin-like growth factor-binding proteins on steroidogenesis by human granulosa cells in culture

The effects of insulin-like growth factor-binding proteins (IGFBPs) 1 and 3 on steroidogenesis by human granulosa cells has been examined. Both IGFBP-1 and IGFBP-3 produced a dose-related inhibition of IGF-I-stimulated oestradiol accumulation in granulosa cell-conditioned medium with complete reversal of the effects of IGF-I in the presence of a molar excess of binding protein. IGFBPs 1 and 3 also exerted a small (25-40%) but significant and consistent inhibition of oestradiol secretion in response to follicle-stimulating hormone (FSH) alone. The progesterone response to IGF-I was inhibited by IGFBPs 1 and 3 but there was no effect on FSH-stimulated progesterone production. These data support the concept of a physiologically important intraovarian IGF system in the human ovary and demonstrate an unequivocally inhibitory effect of IGFBPs 1 and 3 on IGF-I-stimulated granulosa cell steroidogenesis.