Targeted disruption of decorin leads to abnormal collagen fibril morphology and skin fragility

Decorin is a member of the expanding group of widely distributed small leucine-rich proteoglycans that are expected to play important functions in tissue assembly. We report that mice harboring a targeted disruption of the decorin gene are viable but have fragile skin with markedly reduced tensile strength. Ultrastructural analysis revealed abnormal collagen morphology in skin and tendon, with coarser and irregular fiber outlines. Quantitative scanning transmission EM of individual collagen fibrils showed abrupt increases and decreases in mass along their axes. thereby accounting for the irregular outlines and size variability observed in cross-sections. The data indicate uncontrolled lateral fusion of collagen fibrils in the decorindeficient mice and provide an explanation for the reduced tensile strength of the skin. These findings demonstrate a fundamental role for decorin in regulating collagen fiber formation in vivo.     

Obesity and thrombotic vascular diseases

Obesity may either be unspecific as indicated by an increased body mass index (BMI) or due to an abnormal fat-distribution as indicated by an increased waist-to-hip ratio (WHR). The latter is frequently associated with deteriorations of glucose tolerance, hypertriglyceridaemia and hypertension (the metabolic syndrome), a syndrome which is among the strongest risk factors of ischemic heart disease. It is important to note that visceral obesity is a frequent feature of the polycystic ovary syndrome. Also, weight gain after menopause is often associated with a particular increase of the WHR. Obesity as indicated by an increased BMI (> 30 kg/m2) is a weak but easily detectable risk marker of venous thrombotic disease. This risk needs to be considered in clinical practice since obesity was shown to enhance the power of precipitating risk factors of venous disease such as pregnancy, surgery or estrogen treatment.     

Pitfalls in clinical recognition and a novel operative approach for hypertrophic cardiomyopathy with severe outflow obstruction due to anomalous papillary muscle

BACKGROUND: Ventricular septal myotomy/myectomy (Morrow procedure) is the standard surgical option for severely symptomatic patients with hypertrophic cardiomyopathy (HCM) and marked basal obstruction to left ventricular outflow due to mitral valve systolic anterior motion. In some patients, however, congenital malformations of the mitral apparatus may be responsible for outflow obstruction; the failure to recognize this morphology before operation could have adverse consequences. METHODS AND RESULTS: We recently evaluated 2 patients with obstructive HCM operated on at Mayo Medical Center in 1997 who demonstrated direct anomalous papillary muscle insertion into the anterior mitral leaflet, producing muscular midcavity obstruction. This anomaly is potentially identifiable with echocardiography by exaggerated anterior displacement of hypertrophied papillary muscles within the left ventricular cavity and the direct continuity between papillary muscle and anterior leaflet associated with a rigid motion pattern of the mitral apparatus. Echocardiographic diagnosis, however, was confused in both patients by the association of systolic anterior motion of the mitral valve, probably produced by freely mobile margins of the mitral leaflet unencumbered by papillary muscle insertion, and in 1 patient probably representing a second and more basal level of obstruction. Because outflow tract morphology was judged unsuitable for conventional myotomy/myectomy, a novel surgical strategy was designed to remove the outflow gradient in which an extensive myectomy trough (wider at its apical than basal extent) was created within the ventricular septum to papillary muscle level; also, in 1 patient, attachment of anterolateral papillary muscle with the lateral free wall was partially severed to increase mobility of the mitral apparatus. After surgery, both patients reported substantial relief of symptoms and improved exercise tolerance and also showed reduced or abolished basal outflow obstruction. CONCLUSIONS: In HCM, outflow obstruction due to anomalous papillary muscle insertion directly into anterior mitral leaflet is challenging to identify but should always be contemplated before operative intervention. This important (but often unsuspected) congenital malformation may require alternative surgical strategies to standard myotomy/myectomy, similar to those described here.     

Cytokine-induced inhibition of bone matrix proteins is not mediated by prostaglandins

Interleukin-1 (IL-1) and tumor necrosis factor (TNF), two pleiotropic cytokines produced in inflammatory processes, inhibit bone matrix biosynthesis and stimulate prostanoid formation in osteoblasts. In the present study, the importance of prostaglandin formation in IL-1 and TNF-induced inhibition of osteocalcin and type I collagen formation has been examined. In the human osteoblastic cell line MG-63, IL-1 alpha (10-1000 pg/ml), IL-1 beta (3-300 pg/ml) and TNF-alpha (1-30 ng/ml) stimulated prostaglandin E2 (PGE2) formation and inhibited 1,25(OH)2-vitamin D3-induced osteocalcin biosynthesis as well as basal production of type I collagen. Addition of PGE2 or increasing the endogenous formation of PGE2 by treating the cells with arachidonic acid, bradykinin, Lys-bradykinin or des-Arg9-bradykinin, did not affect osteocalcin and type I collagen formation in unstimulated or 1,25(OH)2-vitamin D3-stimulated osteoblasts. Four non-steroidal antiinflammatory drugs, indomethacin, flurbiprofen, naproxen and meclofenamic acid, inhibited basal, IL-1 beta- and TNF-alpha-stimulated PGE2 formation in the MG-63 cells without affecting IL-1 beta- or TNF-alpha-induced inhibition of osteocalcin and type I collagen formation. In isolated, non-transformed, human osteoblast-like cells, IL-1 beta and TNF-alpha stimulated PGE2 formation and concomitantly inhibited 1,25(OH)2-vitamin D3-stimulated osteocalcin biosynthesis, without affecting type I collagen formation. In these cells, indomethacin and flurbiprofen abolished the effects of IL-1 beta and TNF-alpha on prostaglandin formation without affecting the inhibitory effects of the cytokines on osteocalcin biosynthesis. These data show that IL-1 and TNF inhibit osteocalcin and type I collagen formation in osteoblasts independently of prostaglandin biosynthesis and that non-steroidal antiinflammatory drugs do not affect the effects of IL-1 and TNF on bone matrix biosynthesis.     

Induction of specific-locus and dominant lethal mutations in male mice by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU)

1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) induced dominant lethal and specific-locus mutations in male mice. For both compounds the germ cell stage sensitive to the induction of dominant lethal mutations was dose dependent. A dose of 5 mg BCNU per kg b.wt. induced dominant lethal mutations primarily in spermatocytes, whereas higher doses of BCNU induced dominant lethals in spermatids and spermatocytes. Following doses of 5 and 10 mg CCNU per kg b.wt. dominant lethals were induced in spermatids and spermatocytes similar to the results for higher doses of BCNU. Higher dose exposure to BCNU and CCNU was associated with dominant lethals expressed as pre-implantation loss (reduction in total number of implants). In addition, higher doses of CCNU showed a cytotoxic effect in differentiating spermatogonia. Both compounds induced specific-locus mutations in post-spermatogonial germ cell stages of mice. However, CCNU increased also the specific-locus mutation frequency in spermatogonia in two out of three experiments. We conclude in analogy with criteria developed by IARC, that BCNU and CCNU are potential human mutagens.     

FACTORS AFFECTING THE WARPAGE OF SHEET IRON AND STEEL IN ENAMELING1

The effects upon warpage of different methods of cleaning the metal, durations of firing periods, scaling practices, gages of metal, types of enamel, etc., are studied. Test pieces 16 × 16 inches are employed, several commercial enameling irons and steels being used and compared. Warpage is determined by obtaining the areas on five evenly spaced, vertical planes, parallel to one edge of the test piece,‘included between a flat, horizontal base plane and the contour of the test piece resting thereon. The average of the five areas in square centimeters is used to express numerically the degree of warpage. The conclusions are: (a) A wide divergence between the expansivities of the enamel and the metal base induces warpage, (b) there seems to be less tendency for the scaled metal to warp than for that cleaned chemically, (c) thin metal is more sensitive to the factors affecting warpage than thicker metal,(d) sudden, irregular cooling induces warpage, (e) tendency to warpage is reduced by properly supporting the ware during firing and cooling.     

Prostaglandins maintain renal vasodilation and hyperfiltration during chronic nitric oxide synthase blockade in conscious pregnant rats

Rats demonstrate renal vasodilation and hyperfiltration in pregnancy. Because both NO and cGMP biosynthesis are increased in gravid rats and because acute administration of NO synthase inhibitors abrogates renal vasodilation and hyperfiltration, NO most likely mediates the renal circulatory changes of gestation. In the present study, we tested the effect of chronic inhibition of NO synthase on effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) in chronically instrumented, conscious, gravid rats. Because gestation is a relatively long-term condition, we postulated that chronic withdrawal of NO would result in sustained inhibition of renal vasodilation and hyperfiltration. Contrary to our hypothesis, the renal circulatory changes of pregnancy were maintained during chronic blockade of NO synthase. That is, subcutaneous administration of 10 micrograms/min N omega-nitro-L-arginine methyl ester (NAME) for 48 hours did not significantly reduce GFR in either virgin or pregnant rats; thus, hyperfiltration persisted in the latter despite chronic NO synthase blockade. In contrast, ERPF was reduced and effective renal vascular resistance (ERVR) increased in both groups of rats during NAME administration but in a parallel fashion, such that renal vasodilation persisted in the gravid animals despite chronic inhibition of NO synthase. However, with superimposition of acute prostaglandin synthesis inhibition (meclofenamate, 10 mg/kg IV), renal vasodilation and hyperfiltration were abolished; ie, the combined treatments of chronic NO synthase blockade and acute prostaglandin synthesis inhibition led to the equalization of GFR, ERPF, and ERVR in conscious virgin and pregnant rats. Inhibition of prostaglandin synthesis alone had little affect on the renal circulation, as previously reported. In summary, prostaglandins are recruited to maintain renal vasodilation and hyperfiltration during chronic NO synthase blockade in conscious pregnant rats.     

Serum trypsinogen-2 in the prediction of outcome in acute necrotizing pancreatitis

BACKGROUND: The accuracy of serum trypsinogen-2 in predicting the severity of acute necrotizing pancreatitis (ANP) was prospectively evaluated in 52 consecutive patients. METHODS: A new sensitive immunofluorometric assay was used for serum trypsinogen-2, RESULTS: Mean values during the first 24 h were 42.1 micrograms/l in control patients, 1435 micrograms/l in uncomplicated cases, and 4090 micrograms/l in complicated or fatal cases. There was a significant difference in serum trypsinogen-2 values between patients with uncomplicated and complicated disease (p = 0.002) already on admission. When a cutoff level of 1000 micrograms/l was used, patients with uncomplicated ANP were differentiated from patients with complicated ANP with a sensitivity of 91% and with a specificity of 71%. CONCLUSIONS: The immunofluorometric assay of serum trypsinogen-2 is a sensitive and specific method for prediction of the severity of the disease in necrotizing pancreatitis.     

Pretransplantation immunoadsorption therapy in patients immunized with human lymphocyte antigen: effect of treatment and three years' clinical follow-up of grafts

Sensitization against human lymphocyte antigen (HLA) occurs frequently in previously transplanted patients that lose a first cadaveric graft. To shorten their time on the waiting list and reduce the incidence of early rejection in such patients, we performed immunoadsorption therapy by a tryptophan column in 10 patients as an attempt to remove circulating antibodies prior to regrafting. Resynthesis of antibodies was suppressed with cyclophosphamide and prednisolone. Following the course of immunoadsorption therapy, the panel reactive antibodies (PRA) decreased by more than 50% from the pretreatment values. In the present study, 8 patients were transplanted with cadaveric renal grafts. At the time of follow-up, graft survival was 63% in these patients (2-36 months post-transplantation, mean 23 months). There was one incidence of acute rejection, one graft was lost within 48 h owing to renal artery thrombosis, and one was lost within 2 weeks as a result of stenosis. The serum creatinine levels were down to near normal during the first 3 weeks in hospital (p < 0.0001) and remained at this level during the period of follow-up. We conclude that immunoadsorption might be a beneficial pretransplantation therapy and an alternative to plasmapheresis in HLA-immunized patients awaiting kidney transplantation.     

Perioperative ingestion of caffeine and postoperative headache

The interruption of daily consumption of caffeine-containing beverages can cause headache and other symptoms within 8 hours. Resumption of caffeine alleviates these symptoms. Surgical patients routinely fast preoperatively and may have postoperative symptoms from caffeine withdrawal. In the current study, we determined whether perioperative caffeine consumption altered the incidence of postoperative headache. After institutional approval of the study design, 233 surgical outpatients were surveyed about history of headaches, caffeine consumption, and the presence and severity of headaches postoperatively. Of the 233 patients, 190 (82%) drank caffeinated beverages daily (mean daily consumption, 290 mg of caffeine). Postoperative headaches occurred in 22% of patients who routinely drank caffeinated beverages but in only 7% of those who did not (P < 0.03). Other factors associated with postoperative headaches included a history of frequent headaches (P < 0.0001), age of 50 years or younger (P < 0.002), and amount of daily caffeine ingested (P < 0.01). Among daily caffeine drinkers, those who drank caffeinated beverages on the day of the surgical procedure had a lower incidence of postoperative headaches than did those who abstained (17% versus 28%; P < 0.04). Postoperative headaches may be related to several factors. Perioperative intake of caffeine altered postoperative well-being. Caffeine given preoperatively may limit postoperative withdrawal headaches among the millions of daily drinkers of caffeinated beverages. A randomized, prospective, and blinded trial to test this hypothesis is warranted.