The pathophysiology of pancreatitis.

The pancreas is an exocrine and endocrine gland that is required for normal digestion and metabolism of proteins, carbohydrates, and fats. Acute pancreatitis (AP) is an inflammatory process of the pancreas that involves peripancreatic tissues and remote organs. Mild AP occurs in 80% of patients requiring hospitalization and severe AP occurs in the other 20%. Chronic pancreatitis (CP) is an inflammatory disorder that causes anatomic changes, including infiltration of chronic inflammatory cells and fibrosis of the pancreas. This review discusses biochemical and histologic features of pancreatic injury in AP and CP and some of the important clinical sequelae associated with these abnormalities.     

Tip position of long-term central venous access devices used for parenteral nutrition

BACKGROUND: Venous thrombosis is a potential postplacement complication of a central venous access device (VAD). Improper catheter tip position is a predisposing factor, especially when the device is used to administer parenteral nutrition (PN). American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) guidelines recommend that a central VAD used for PN be placed with its tip in the superior vena cava (SVC) adjacent to the right atrium (RA). The purpose of this study is to determine the prevalence of improper central VAD tip position and factors associated with malpositioning. METHODS: All adult patients with a longterm VAD (ie, tunneled central venous catheter, peripherally inserted central catheter [PICC], or implanted port) placed before the current admission who were scheduled to receive PN also received chest x-rays to evaluate position of the catheter tip. Position was determined by a staff radiologist. A catheter with its tip ranging from the middle third of the SVC to the RA was considered acceptable; a catheter with its tip in any other position was considered malpositioned. Subjects with multiple VADs or multiple evaluations for the same catheter had the first placement and last evaluation considered. A logistic regression analysis was used to study the univariable and multivariable associations of these factors with tip malposition. RESULTS: Data were collected for catheters in 124 patients, including 74 tunneled catheters (71 Hickman, 2 Broviac, 1 Groshong), 38 PICCs, and implanted ports. Most of the catheters were placed for (81.9%) or chemotherapy (14.5%). Median catheter duration was 1.6 months at time of evaluation. Of 138 catheters studied, 15.9% (95% confidence interval, 10.2-23.1) were malpositioned at time of evaluation. According to univariable analysis, factors associated with malpositioned catheters included shorter catheter duration (p = .001), greater number of lumens (p = .029), venous entry site on the arm (p <.001) and catheters placed at institutions other than Cleveland Clinic (p = .007). Additionally, PICCs were likely to be malpositioned at time of evaluation compared with other long-term VADs combined (34.2% vs 9.0%; p < .001). CONCLUSIONS: A high percentage of long-term VADs improperly positioned for PN in the present study. were more likely to be malpositioned at time of evaluation compared with tunneled catheters and implanted These findings suggest the tip position of long-term should be confirmed before infusing PN.     

A common genetic variation in the 3'-untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis

We have examined the prothrombin gene as a candidate gene for venous thrombosis in selected patients with a documented familial history of venous thrombophilia. All the exons and the 5'- and 3'-UT region of the prothrombin gene were analyzed by polymerase chain reaction and direct sequencing in 28 probands. Except for known polymorphic sites, no deviations were found in the coding regions and the 5'-UT region. Only one nucleotide change (a G to A transition) at position 20210 was identified in the sequence of the 3'-UT region. Eighteen percent of the patients had the 20210 AG genotype, as compared with 1% of a group of healthy controls (100 subjects). In a population-based case-control study, the 20210 A allele was identified as a common allele (allele frequency, 1.2%; 95% confidence interval, 0.5% to 1.8%), which increased the risk of venous thrombosis almost threefold odds ratio, 2.8; 95% confidence interval, 1.4 to 5.6. The risk of thrombosis increased for all ages and both sexes. An association was found between the presence of the 20210 A allele and elevated prothrombin levels. Most individuals (87%) with the 20210 A allele are in the highest quartile of plasma prothrombin levels (> 1.15 U/mL). Elevated prothrombin itself also was found to be a risk factor for venous thrombosis.     

Blastomycosis in a young African man presenting with a pleural effusion

Blastomyces dermatitidis is a dimorphic fungus endemic to northwestern Ontario, Manitoba and some parts of the United States. The fungus is also endemic to parts of Africa. Pulmonary and extrapulmonary findings of a 24-year-old African man who presented with weight loss, dry cough and chronic pneumonia not resolving with antibiotic treatment are presented. The unusual occurrence of pulmonary blastomycosis associated with skin lesions and a moderate pleural effusion is reported.     

Cumulative effects of repeated surfactant treatments in the rabbit

The responses of the adult rabbit lung to multiple doses of surfactant after intratracheal injections of either natural calf surfactant or Surfactant-TA were evaluated. For each surfactant, four groups of 1.4-kg rabbits were studied: group 1 received 100 mg of surfactant containing isotopically-labeled dipalmitoylphosphatidylcholine; group 2 received the same labeled surfactant and then three tracheal injections of vehicle; group 3 received labeled surfactant and then three doses (100 mg) of unlabeled surfactant; group 4 was treated in the same way as group 3 except that the final dose was of the labeled surfactant. All rabbits were killed, and alveolar washes were recovered 24 h after the labeled surfactant dose had been given. The amount of labeled palmitate-saturated phosphatidylcholine (Sat PC) in alveolar washes did not change after multiple doses of calf surfactant, indicating that subsequent doses did not alter the clearance of previous doses. The four doses of calf surfactant increased the alveolar Sat PC pool size by a factor of 2.5 only when measured 6 h after the last dose, but the total lung Sat PC pool size doubled, indicating a loss of most of the surfactant Sat PC to the lung tissue. In contrast, Surfactant-TA increased the alveolar pool size by a factor of 4 after the single dose and by a factor of 11 after the multiple doses, and the percentage clearance of labeled Sat PC from the lungs decreased with multiple doses, indicating an effect of subsequent doses on the initial dose. The quantity of Sat PC cleared from the lungs increased by about a factor of 2 after the multiple doses of Surfactant-TA. Although repetitive surfactant doses changed alveolar and lung Sat PC pool sizes the quantity of Sat PC cleared from the lungs increased, and the lungs accommodated the large amount of surfactant without short-term adverse effects.     

Type IIB Tampa: a variant of von Willebrand disease with chronic thrombocytopenia, circulating platelet aggregates, and spontaneous platelet aggregation

Type IIB von Willebrand disease is characterized by enhanced ristocetin- induced platelet aggregation and absence of large von Willebrand factor multimers from plasma. An alteration of the von Willebrand factor molecule resulting in increased reactivity with platelets appears to be the basis for these abnormalities. We have now identified a new variant of type IIB von Willebrand disease in a family in which the four affected members also have chronic thrombocytopenia, in vivo platelet aggregate formation, and spontaneous platelet aggregation in vitro. In spite of repeatedly prolonged bleeding times and persistent thrombocytopenia, their bleeding diathesis is only moderate.