Collagen Fibrillogenesis in Tissues, in Solution and from Modeling: A Synthesis

Collagen fibril formation has been studied in tissues by light and electron microscopy; in solution by light scattering and microscopy; and from modeling based on the amino acid sequence of type I collagen. Taken together these studies indicate that collagen fibril assembly involves a stepwise formation of intermediate aggregates in which each intermediate is formed from earlier aggregates. In this sequence, monomeric collagen contributes only to the formation of early aggregates; and fibrils grow in length by the addition of intermediate aggregates to the end of a subfibril and in width by lateral wrapping of subfibrils. Modeling based on amino acid sequence data of possible intermolecular charge-charge interactions indicate 2 different kinds, one which promotes linear aggregation and the other which promotes lateral aggregation. The effects of different colla-gens and coprecipitants such as glycoproteins and proteoglycans can begin to be explained by their influence on the character of intermediate subassemblies. Ultrastructural data from 2 tissues, embryonic cornea and tendon, indicate that the site of fibril growth and assembly is at the cell surface

Intraperitoneal Catheter Placement: The “Hammock” Technique

AbstractBackgroundOvarian cancer is the leading cause of death from gynecologic malignancies in the United States. The NCI released a clinical announcement supporting the use of intraperitoneal chemotherapy in addition to intravenous chemotherapy. However, multiple trials have shown that IP administration is severely limited by catheter complications.PurposeWe present a new technique for inserting and securing IP catheters in order to prevent the previously reported complications, in particular obstruction of the catheter, bowel and vaginal cuff perforation.MethodsFrom March 2006 through February 2010, 38 patients with stage III or IV ovarian cancer underwent optimal cytoreductive surgery and had an IP catheter placed via the “Hammock” technique.Results14 patients underwent modified posterior exenteration (37%); 6 underwent splenectomy (16%); thirteen small bowel resections (34%). All 38 patients underwent pelvic and aortic lymphadenectomy. Two patients had reservoir complications; one “flipped over”, and the other had an infection at the port site. Both patient’s elected to discontinue the IP portion of the chemotherapy regimen. 219 cycles of chemotherapy were completed (96%) out of a possible 228 cycles. The only complications were related to the reservoir. There were no catheter-related complications.ConclusionAs an increasing number of IP catheters are placed at the time of cytoreductive surgery, we will continue to have catheter complications and IP chemotherapy administration difficulties. In using the “Hammock” Technique, we had no catheter complications, and a 96% chemotherapy completion rate. We recommend using the “Hammock” Technique for inserting and securing IP catheters at the time of cytoreductive surgery.

Chondroitin Sulfate Proteoglycans Are a Common Component of Neuronal Inclusions and Astrocytic Reaction in Neurodegenerative Diseases

Previously, we showed three differentially sulfated forms of chondroitin sulfate proteoglycans (CSPG) associated with senile plaques, astrocytes and neurofibrillary tangles in Alzheimer\u27s disease. Here, monoclonal antibodies were used to demonstrate CSPGs in other neurodegenerative diseases. CSPGs were found associated with inclusions of Parkinson\u27s, diffuse Lewy body, Pick\u27s diseases, and progressive supranuclear palsy. Reacting astrocytes in each of these neurodegenrative diseases and Huntington\u27s disease showed immunoreactivity for CSPG. CSPG distribution in a variety of neurodegenerative diseases suggests that similar mechanisms may be involved in the accumulation of proteoglycans in a number of filamentous inclusions

Letters and Corrections

Letters submitted for possible publication must be identified as such and submitted with a signed transfer-of-copyright form (see Life Expectancies: Population or Person? To the Editor: We applaud Sox and colleagues' analysis (1) of the role of exercise testing in coronary artery disease. We are concerned, however, with the interpretation of the results, specifically, how one assesses the average change in the life expectancy for an entire cohort as opposed to a change for a single individual. The authors state, for example, that for 60-year-old men with at least one risk factor, the average increase in life expectancy for the cohort is 17 days. However, given that the prevalence of disease is presumed to be 0.15, the average change in life expectancy for someone who actually has the disease is 17/0.15 or 113 days (and would be even higher for those with left main disease). This figure compares favorably with the 110 days of life gained by reducing diastolic blood pressure from 110 to 90 mm Hg in 60-year-old men with hypertension. We believe that many people do not appreciate the meaning of marginal differences in life expectancy and that there is great variation among judgments of what constitutes trivial extensions of life expectancy (2). The population-based number of 17 days may have a different meaning to some than the 113-day Framing effects are well known (3), and the authors (1) include a section on other ways to express results using a variant of the number-needing-treatment method of Laupacis and colleagues (4). We believe, however, that the average life expectancy gain of the cohort is an outcome measure that obscures information needed by patients to make decisions. We suggest that life expectancy gains for those with the disease should also be represented. In that way doctors and patients can best use population-based life expectancy figures for decision-making. In response: Screening and other diagnostic strategies are invariably applied to heterogeneous populations. There are always at least two subgroups: those with and those without the disease. In our report (1), the summary estimate of 17 days of life is a weighted average of the therapeutic outcomes for members of each group, where the weights are the probabilities of being in each of the groups. It would be misleading to present the larger figure for life gained (113 days for the 15% who prove to have disease) without reference to the fact that this estimate is conditional upon being in the small subgroup of participants who have disease. These groups could be divided further-for example, into subgroups of diseased patients based on their coronary anatomy. Then the benefit in the highest-risk subgroup would be even greater. However, all who are screened, including the majority who do not benefit, bear the costs and risks of the strategy. As an extreme example, a strategy of monthly computed tomographic scans to detect lung cancer might yield large benefits for the few subjects who are spared death, but to assess the value of such a strategy we must include the impact upon the many people who do not have disease and would not be saved (and, indeed, could be harmed) by the strategy. We agree that the way results are presented can influence the way they are interpreted. Readers who prefer more detailed analysis or alternative presentations of results can find in our article (1) the probabilities and life expectancies associated with each branch of the decision tree. Because the results and assumptions of our analysis are described explicitly, our findings are subject to sensitivity analysis, review, revision, and debate. We feel that the cost-effectiveness ratio is the most informative, succinct summary of the results of the analysis. However, a summary estimate is just that: a summary. We hope that decision-makers will take advantage of the data presented in our analysis to inform their decision-making to the level of detail that best suits their own purposes. Alan Cardiac Rehabilitation Services and Risk Reduction To the Editor: The review by Drs. Greenland and Chu (1) on cardiac rehabilitation services and the accompanying position paper (2) developed by the Health and Policy Committee, American College of Physicians base their discussions of program components on a definition of cardiac rehabilitation that focuses on the restorative function of this intervention. Although programs for cardiac rehabilitation were originally based on a restorative model of care Also of concern are the conclusions regarding exclusion criteria reached by the Health and Public Policy Committee in the accompanying position paper (2), which was also authored by Drs. Greenland and Chu. With recent angiographic evidence of atherosclerotic regression in the coronary, carotid, and peripheral circulations of human subjects who have lowered their serum cholesterol levels dramatically (5), it seems limiting to suggest that only those persons with a demonstrated "cardiac-related disability in physical capacity" are appropriate candidates for cardiac rehabilitative effort (2). In its concluding remarks, the Committee proposes a judicious selection of candidates for the estimated $108 million spent annually on cardiac rehabilitation efforts. This sum is minimal, however, when compared with the billions of dollars spent on palliation of the vascular complications of atherosclerosis, which have been shown to be modified, if not avoided, by the risk-factor modification efforts of cardiac rehabilitation programs. All would agree that controlling the growth of the national health-care budget is long overdue, yet limiting the growth of cardiac rehabilitation programs rather than increasing programs to reduce risks for the population at large and for those already affected by coronary heart disease can only increase the burden of atherosclerotic diseases and the costs of their "high tech" treatments. population of patients. I concur with Dr. Downing that a rationale exists upon which physicians and other health-care professionals might offer services for risk-factor reduction to many groups of patients not covered specifically by our critique of cardiac rehabilitation services. However, in the review (1) we stated clearly that our analysis was based on a "critical review of the published articles on the benefits and risks of cardiac rehabilitation services. . . with primary emphasis on the role of cardiac rehabilitation after myocardial infarction." We also stated that "many survivors of myocardial infarction could theoretically benefit from organized attempts to help them stop smoking, lower their blood lipids, and control hypertension or other standard risk factors." The question we intended to address in our review was whether the published medical literature supports the application of specialized cardiac rehabilitation services as an especially effective means of reducing cardiac risk factors in patients with coronary artery disease-not whether such treatments could be of theoretical benefit to this group of patients. As we noted, there is no body of published evidence to support the routine addition of treatments for riskfactor reduction to organized cardiac rehabilitation services for survivors of myocardial infarction. For that matter, I could find no evidence that routine efforts at risk-factor reduction in the form of organized programs are preferable to other forms of medical care for primary or secondary prevention of coronary artery disease. Consequently, our conclusions could not advocate or support the use of such treatments, even though, as Dr. Downing points out, such efforts have theoretical appeal. Jill Downing, MD I applaud the efforts of those interested in primary, secondary, or tertiary prevention of coronary artery disease and challenge clinical scientists to promote research that will support the addition of such clinical services on a more routine basis in the future. Philip Greenland, MD SI and Presently Conventional Units To the Editor: Having grown up in the era of metric units, I am pleased to see that medical literature is finally adopting SI units (le Systeme internationale d'Unites). It is especially fitting now that research has clearly become more international, with workers from many countries often laboring on the same projects simultaneously. Problems always emerge with any attempt at modernization, however, including the chance that those unfamiliar with the new systems will be left behind. This particular problem surfaced for me after reading the article (1) on methylprednisolone therapy in alcoholic hepatitis by Carithers and colleagues. The study design, methods, eligibility criteria, and results were clearly stated, and the article was well worth clipping and saving. As I was putting it in my file, however, I tried mentally to compare the patients featured with my own. Just how severe was the hepatitis described? Was the bilirubin concentration 5 times normal? 20 times normal? No normal values were given in the new SI units. It is a simple matter to convert miles to kilometers, and pounds to kilograms, but to convert SGOT levels from international units per litre to microkatals per litre, bilirubin concentrations from micromoles to milligrams per decilitre, and so on, requires the memorization of molecular weights and catalytic constants. It simply discourages the comparison of pre-SI with post-SI patients. To make matters worse, the patients featured in this article (1) were accrued from 1979 to 1984, a period in which no one in American medicine used SI units. Thus, the data must have been converted to SI format for publication, and the conversion factors then removed from the manuscript. There is no reason to close off the literature from those readers whose laboratory slips may still express values in milligrams per decilitre. Simply print the normal ranges for the new units when they are first mentioned in the article, and even the most Neanderthal of medical readers will have some point of reference from which to begin counting on his (opposable) thumbs. We do offer authors the option of including present metric units with SI units, and only a fraction of authors ask for it. Dr. Giacoppe's view is reasonable, and we shall suggest to authors that they include non-SI units, at least for measurements that are central evidence for a paper's main conclusion. -The Editor The Metaraminol Test and Adverse Cardiac Effects To the Editor: Familial Mediterranean fever (FMF) is a hereditary disorder of unknown cause. The diagnosis is not difficult when a family history is relevant and diagnostic criteria are met (1, 2). Barakat and colleagues A 38-year-old woman had a family history of familial Mediterranean fever and occasionally had diffuse abdominal tenderness. She reported no history of fever, chest pain, arthralgia, or skin manifestations, and she did not have hypertension or cardiac disease. In view of a possible diagnosis of familial Mediterranean fever, and with informed consent of the patient, a metaraminol test was done. A baseline, standard electrocardiogram (ECG) was obtained, and supine blood pressure, pulse rate, and temperature were recorded. Throughout the test period the patient was monitored. An intravenous infusion of normal saline, 500 mL, to which was added a 10-mg dose of metaraminol bitartrate, was given for 4 hours. Thirty minutes after beginning the test, the patient had chest pain with coronary characteristics and palpitations. An ECG showed a bigeminal rhythm. The metaraminol infusion was discontinued, and 5 minutes later the patient was asymptomatic, and the ECG was normal. A week later, an exercise ECG was negative. Although Barakat and colleagues (4) did not report any serious side effects in their experience with metaraminol tests (80 cases), we agree with Cattan and colleagues (5) that this test is not harmless and that it should not be used unless absolutely necessary, possibly in patients with paucisymptomatic forms of lateonset familial Mediterranean fever who do not have a relevant family history. We think the criteria established by Sohar and colleagues (1) and Eliakim and colleagues (2) and a family history are sufficient for the diagnosis of most cases. Collagenous Colitis and Histiocytic Lymphoma To the Editor: Collagenous colitis is a relatively rare cause of watery diarrhea and abdominal pain and is characterized histologically by a thickened band of collagen beneath the colonic mucosa epithelium. I report a case of collagenous colitis associated with diffuse histiocytic lymphoma, which responded to sulfasalazine and steroid enemas, even as lymphoma progressed. A 78-year-old woman with a 1-year history of diarrhea was admitted in February 1988 for a presumed stroke with mild aphasia. In the past year she had had four to five loose stools per day. At admission, cultures of the stool and examination for ova and parasites were negative. Colonoscopy was done and was remarkable only for decreased haustral markings. A random biopsy sample showed thickened subepithelial collagen deposition consistent with collagenous colitis. Staining of the biopsy sample was negative for iron and amyloid. She was treated with sulfasalazine and steroid enemas with resolution of her diarrhea. Magnetic resonance imaging of her head showed a parietal lesion, a biopsy specimen of which showed diffuse histiocytic lymphoma. She was not considered a candidate for chemotherapy and had skin-flap closure with palliative cranial radiation therapy. Progression of her lymphoma was manifested by increased cervical lymphadenopathy. She died, and an autopsy was not done. A patient with Hodgkin lymphoma and collagenous colitis has been described (1). In this case, collagenous colitis was thought to reflect a paraneoplastic phenomenon. The patient's diarrhea showed significant improvement after both treatment with prednisone-based chemotherapy and clinical improvement of her lymphoma. Collagenous colitis can have a variable course (2), and spontaneous resolution without therapy has been reported (3). Therefore, it is difficult to assess treatment success in patients with collagenous colitis. The patient with Hodgkin lymphoma had been treated with a corticosteroid, which has been used successfully in the past for treating collagenous colitis (2, 4, 5). It is unclear whether the collagenous colitis improved because of the prednisone or because of the improvement of the lymphoma after chemotherapy. A paraneoplastic phenomenon, however, would not be a consideration in my patient because her diarrhea resolved after treatment with sulfasalazine and local steroid enemas. Sulfasalazine has not been shown to have any effect on lymphomas. Although there may be systemic absorption of the steroid from the enemas, the patient's diarrhea improved even as lymphoma progressed. Collagenous colitis is a rare disease and its exact incidence has yet to be determined. The finding of lymphoma in two patients with collagenous colitis may suggest that an association exists. DavidB. Edwards, MD Pancytopenia and Methotrexate with TrimethoprimSulfamethoxazole To the Editor: Kozarek and colleagues (1) found a dramatic clinical improvement in patients treated with methotrexate who had refractory Crohn colitis and an incomplete remission of chronic ulcerative colitis. Of 21 patients, 14 were also receiving either sulfasalazine or metronidazole (exact number of patients not mentioned). The risk of bone marrow suppression is increased when other antifolate drugs (derivatives of sulfonamides, trimethoprim) are used simultaneously with methotrexate. Besides additive folate antagonism, other pharmacologic mechanisms, such as competition with tubular secretion and displacement from albumin binding sites, play an important role in interactions of sulfonamides and methotrexate. Moreover, it was shown that sulfasalazine inhibits the hydrolysis of polyglutamyl folate and the intestinal transport of folate in patients with ulcerative colitis (2). Pancytopenia due to the combined use of methotrexate and trimethoprim-sulfamethoxazole has been reported in two patients with rheumatoid arthritis (3, 4). We report two additional cases of this severe side effect. In case 1, an 81-year-old woman had refractory rheumatoid arthritis and impaired renal function (creatinine, 166 jixmol/L) and was treated with methotrexate, 5 mg weekly for 6 weeks. Cystitis {Escherichia coli) was treated with trimethoprim, 300 mg daily. One week after starting trimethoprim, bone marrow suppression developed (leukocytes, 1.9 X 10VL; platelets, 15 X 10VL; hemoglobin, 6.3 mmol/L). Both methotrexate and trimethoprim were discontinued. Blood cell counts returned to normal in 2 weeks. One month after discharge she died of severe bronchopneumonia (determined at autopsy). In case 2, a 7 5-year-old woman with refractory rheumatoid arthritis and impaired renal function (estimated creatinine clearance, 40 mL/min) was receiving methotrexate, 5 mg weekly. A recurrent cystitis was treated with trimethoprim-sulfamethoxazole. Shortly after beginning trimethoprim-sulfamethoxazole, bone marrow suppression developed (hemoglobin, 5.6 mmol/L; leukocytes, 1.6 X 10 9 /L; platelets, 23 X 10VL). A bone marrow biopsy specimen showed hypocellularity. Both drugs were discontinued, and therapy with leucovorin was begun; she recovered in several weeks. These two patients were not treated with the combination of sulfasalazine and methotrexate; however, other antifolate drugs were used in conjunction with methotrexate. Additive folate antagonism, independent of which antifolate drug was used simultaneously with methotrexate, seemed to play a central role in inducing bone marrow suppression in these patients. We do not recommend prescribing other drugs with antifolate action simultaneously with methotrexate. The toxicity of and the possibility of adverse drug interactions with methotrexate are increased in the presence of other risk factors such as old age, hypalbuminemia, impaired renal function, and decreased bone marrow reserve (5). Acknowledgment: We thank Drs. J. Rasker, W. Hissink Muller, and J. Haverman for allowing us access to their patients

Trypanosoma cruzi Utilizes the Host Low Density Lipoprotein Receptor in Invasion

Trypanosoma cruzi, an intracellular protozoan parasite that causes Chagas disease in humans and results in the development of cardiomyopathy, is a major health problem in endemic areas. This parasite can invade a wide variety of mammalian cells. The mechanisms by which these parasites invade their host cells are not completely understood. Our study highlights, for the first time, that the Low Density Lipoprotein receptor (LDLr) is important in the invasion and the subsequent fusion of the parasitophorous vacuole with host lysosomes. We demonstrate that T. cruzi directly binds to LDLr, and inhibition or disruption of LDLr significantly decreases parasite entry. Additionally, we have determined that this cross-linking triggers the accumulation of LDLr and phosphotidylinositol phosphates in coated pits, which initiates a signaling cascade that results in the recruitment of lysosomes, possibly via the sorting motif in the cytoplasmic tail of LDLr, to the site of adhesion/invasion. Studies of infected CD1 mice demonstrate that LDLs accumulate in infected heart and that LDLr co-localize with internalized parasites. Overall, this study demonstrates that LDLr and its family members, engaged mainly in lipoprotein transportation, are also involved in T. cruzi entry into host cells and this interaction likely contributes to the progression of chronic cardiomyopathy

Sleep During Pregnancy: The nuMoM2b Pregnancy and Sleep Duration and Continuity Study

Study Objectives: To characterize sleep duration, timing and continuity measures in pregnancy and their association with key demographic variables. Methods: Multisite prospective cohort study. Women enrolled in the nuMoM2b study (nulliparous women with a singleton gestation) were recruited at the second study visit (16-21 weeks of gestation) to participate in the Sleep Duration and Continuity substudy. Women <18 years of age or with pregestational diabetes or chronic hypertension were excluded from participation. Women wore a wrist activity monitor and completed a sleep log for 7 consecutive days. Time in bed, sleep duration, fragmentation index, sleep efficiency, wake after sleep onset, and sleep midpoint were averaged across valid primary sleep periods for each participant. Results: Valid data were available from 782 women with mean age of 27.3 (5.5) years. Median sleep duration was 7.4 hours. Approximately 27.9% of women had a sleep duration of 9 hours. In multivariable models including age, race/ethnicity, body mass index, insurance status, and recent smoking history, sleep duration was significantly associated with race/ethnicity and insurance status, while time in bed was only associated with insurance status. Sleep continuity measures and sleep midpoint were significantly associated with all covariates in the model, with the exception of age for fragmentation index and smoking for wake after sleep onset. Conclusions: Our results demonstrate the relationship between sleep and important demographic characteristics during pregnancy

NQO1-Bioactivatable Therapeutics as Radiosensitizers for Cancer Treatment

Developing cancer therapeutics that radiosensitize in a tumor-selective manner remains an ideal. We developed a novel means of radiosensitization, exploiting NAD(P)H:Quinone Oxidoreductase 1 (NQO1) overexpression, and lowered catalase expression in solid human tumors using NQO1-bioactivatable drugs. Non-small cell lung (NSCLC), pancreatic (PDAC), prostate, and breast cancers overexpress NQO1. Ionizing radiation (IR) creates a spectrum of DNA lesions, including lethal DNA double-strand breaks (DSBs), and mutagenic but rarely lethal altered DNA bases and DNA single-strand breaks (SSBs). NQO1-bioactivatable drugs (e.g., β-lapachone and deoxynyboquiones) also promote abasic DNA lesions and SSBs. These hyperactivate poly (ADP-ribose) polymerase 1 (PARP1) and dramatically increase calcium release from the endoplasm reticulum (ER). Exposure of human cancer cells overexpressing NQO1 to NQO1-bioactivatable drugs immediately following IR, therefore, hyperactivates PARP1 synergistically, which in turn depletes NAD+ and ATP, inhibiting DSB repair. Ultimately, this leads to cell death. Combining IR with NQO1-bioactivatable drugs allows for a reduction in drug dose. Similarly, a lower IR dose can be used in combination with the drug, reducing the effects of IR on normal tissue. The combination treatment is effective in preclinical animal models with NSCLC, prostate, and head and neck xenografts, indicating that clinical trials are warranted