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Biomedical subjects

M M Jonas

Publications and source records attributed to M M Jonas.

At least 19 recordsLinked to original sources
PubMed2004

Non-invasive cardiac output monitoring.

Outcomes in the management of critically ill patients may be improved using goal-directed peri-operative haemodynamic monitoring. A conservative approach may no longer be acceptable but in view of the significant morbidity associated with balloon tipped flow directed pulmonary artery catheters a non-invasive approach would be preferable. In this review we consider the different non-invasive techniques available and discuss the advantages and disadvantages of each technique.

Blood Pressure↗
PubMed2001

Outcome of intravenous immunoglobulin-transmitted hepatitis C virus infection in primary immunodeficiency.

Physicians in the United States who treat patients with primary immunodeficiency were contacted to identify subjects who had been infected with hepatitis C due to exposure to contaminated intravenous immunoglobulin (IVIg) in 1993-1994. From this survey we gathered information on 58 PCR-positive hepatitis C-infected patients; 37 had CVID, 9 had XLA, 5 were IgG subclass deficient, 4 were antibody deficient with normal immunoglobulin levels, 2 had SCID after BMT, and 1 had B cell linker deficiency. Of the 58 subjects, 30 had been treated with IFN-alpha in combination with ribavirin in 5 cases, and 26 other subjects were not treated. Of those who were treated, 11 (37%) resolved the infection and became PCR-negative; of the 26 who were not treated, 5 (19%) have resolved the infection, outcomes not significantly different. Patients 20 years of age or younger had a significantly better outcome compared to those older than age 20 (P = 0.02). Five subjects of the 58 have had a liver transplantation, a sixth has had two transplants, and 10 (17%) of the group have died. This survey demonstrates the heterogeneity of the clinical outcome in subjects with primary immunodeficiency who contracted hepatitis C due to viral contamination of IVIg.

Adolescent↗
PubMed2001

Challenges in the treatment of hepatitis C in children.

Hepatitis C infection in children is associated with a unique set of challenges for clinicians and investigators. Although the prevalence of HCV infection is lower in children than in adults, it is important to identify infected children to monitor progression of liver disease and to make appropriate interventions to minimize factors that may exacerbate progression. Identification requires understanding of risk factors important in children, primarily exposure at or near the time of birth. The natural history of this infection in most children is either more benign or significantly prolonged than that of infection acquired in adulthood. Reasons for this difference in natural history must be explored and possibly even exploited in the care of adult patients with HCV infection. Identification of appropriate pediatric candidates for treatment and definition of optimal therapy for these children require ongoing study. Lastly, as perinatal transmission becomes the primary mode of acquisition for new pediatric infections, factors that increase or decrease the likelihood of this transmission must be identified, and effective preventive interventions must be put into practice. There are important differences in the clinical features, natural history, and response to therapy between pediatric and adult patients with HCV infection. Understanding of these differences will allow optimal care for affected children and perhaps better understanding of the pathophysiology and pure natural history of this disease.

Antiviral Agents↗
PubMed2000

Cardiac output measured by lithium dilution and transpulmonary thermodilution in patients in a paediatric intensive care unit.

OBJECTIVE: To compare the results of cardiac output measurements obtained by lithium dilution and transpulmonary thermodilution in paediatric patients. DESIGN: A prospective study. SETTING: Paediatric intensive care unit in a university teaching hospital. PATIENTS: Twenty patients (age 5 days-9 years; weight 2.6-28.2 kg) were studied. INTERVENTIONS: Between two and four comparisons of lithium dilution cardiac output (LiDCO) and transpulmonary thermodilution (TPCO) were made in each patient. MEASUREMENTS AND RESULTS: Results from three patients were excluded: in one patient there was an unsuspected right-to-left shunt, in two patients there was a problem with blood sampling through the lithium sensor. There were 48 comparisons of LiDCO and TPCO in the remaining 17 patients over a range of 0.4-6 l/min. The mean of the differences (LiDCO-TPCO) was -0.1 +/- 0.3 (SD) l/min. Linear regression analysis gave LiDCO = 0.11 + 0.90 x TPCO l/min (r2 = 0.96). There were no adverse effects in any patient. CONCLUSIONS: These results suggest that the LiDCO method can be used to provide safe and accurate measurement of cardiac output in paediatric patients. The method is simple and quick to perform, requiring only arterial and venous catheters, which will already have been inserted for other reasons in these patients.

Age Factors↗
PubMed2000

Viral hepatitis. From prevention to antivirals.

The challenge of viral hepatitis has been acknowledged and confronted in the last decade. Significant progress in prevention of infection with HAV and HBV may eradicate these serious infections from the United States and other parts of the world in the coming decades. Application of prophylactic strategies to children will be a major mechanism in accomplishing this task. The quest for potent antiviral medications continues. The next critically important development will be ways to prevent new HCV infections and to treat the millions of already infected individuals at risk for the serious consequences of this disease. For pediatricians, realizing these goals requires a greater understanding of perinatal HCV transmission, use of vaccines for prevention of viral hepatitis, and identification of HCV-infected children who are likely to benefit from new therapeutic strategies as they become available.

Antiviral Agents↗
PubMed2000

Cardiac output measured by lithium dilution, thermodilution, and transesophageal Doppler echocardiography in anesthetized horses.

OBJECTIVE: To assess the suitability of lithium dilution as a method for measuring cardiac output in anesthetized horses, compared with thermodilution and transesophageal Doppler echocardiography. ANIMALS: 6 horses (3 Thoroughbreds, 3 crossbreeds). PROCEDURE: Cardiac output was measured in 6 anesthetized horses as lithium dilution cardiac output (LiDCO), thermodilution cardiac output (TDCO), and transesophageal Doppler echocardiographic cardiac output (DopplerCO). For the LiDCO measurements, lithium chloride was administered i.v., and cardiac output was derived from the arterial lithium dilution curve. Sodium nitroprusside, phenylephrine hydrochloride, and dobutamine hydrochloride were used to alter cardiac output. Experiments were divided into 4 periods. During each period, 3 LiDCO measurements, 3 DopplerCO measurements, and 3 sets of 3 TDCO measurements were obtained. RESULTS: 70 comparisons were made between LiDCO, DopplerCO, and triplicate TDCO measurements over a range of 10 to 43 L/min. The mean (+/- SD) of the differences of LiDCO - TDCO was -0.86 +/- 2.80 L/min; LiDCO = -1.90 + 1.05 TDCO (r = 0.94). The mean of the differences of DopplerCO - TDCO was 1.82 +/- 2.67 L/min; DopplerCO = 2.36 + 0.98 TDCO (r = 0.94). The mean of the differences of LiDCO - DopplerCO was -2.68 +/- 3.01 L/min; LiDCO = -2.53 + 0.99 DopplerCO (r = 0.93). CONCLUSIONS AND CLINICAL RELEVANCE: These results indicate that lithium dilution is a suitable method for measuring cardiac output in horses. As well as being accurate, it avoids the need for pulmonary artery catheterization and is quick and safe to use. Monitoring cardiac output during anesthesia in horses may help reduce the high anesthetic mortality in this species.

Animals↗
PubMed1999

Treatment of chronic hepatitis C in pediatric patients.

Although HCV infection in children shares some clinical features with that in adults, it is clearly different in several ways. These differences may have important implications for treatment. Some differences, such as milder disease, less frequent extrahepatic manifestations, and fewer comorbid conditions causing progression, argue against aggressive treatment in childhood. Other factors, such as less severe liver disease, shorter disease duration, possibly higher rates of sustained virologic response, and better tolerance of IFN, may be reasons to pursue treatment before advanced hepatic injury occurs. Given the relatively small number of pediatric patients with HCV infection and the gaps in the current understanding of natural history and effects of therapy in these patients, treatment should be undertaken only in clinical trials, so that careful data collection and monitoring can define more precisely the safety and efficacy of IFN therapy in children.

Child↗
PubMed1999

A comparison of lithium dilution cardiac output measurements made using central and antecubital venous injection of lithium chloride.

OBJECTIVE: We have previously described an indicator dilution technique of measuring cardiac output in which lithium chloride is injected as a bolus via a central venous catheter and cardiac output derived from the arterial lithium dilution curve recorded from a lithium-selective electrode, which we have developed for this purpose. It would be an advantage if the lithium could be injected via the basilic vein (in the antecubital fossa) in those patients who do not need central venous catheterisation for other reasons. We have therefore compared cardiac output measurements made using these two routes of lithium chloride administration. METHODS: Lithium dilution cardiac output was measured 10 times in each of 10 patients, injecting the lithium chloride alternately via the basilic or central venous catheter. RESULTS: The mean difference was 0.8 +/- 5.2% (SD) (range -8.5 to +7.0%) over a range of cardiac output of 4.5-13 l/min. CONCLUSIONS: Injection of lithium chloride via the basilic vein in the antecubital fossa allows accurate lithium dilution cardiac output measurements to be made in patients who do not have central venous catheters in place.

Adjuvants, Immunologic↗
PubMed1999

A new technique for measuring cardiac output and shunt fraction during venovenous extracorporeal membrane oxygenation.

A new indicator dilution technique is described for measuring cardiac output and shunt fraction in patients undergoing venovenous extracorporeal membrane oxygenation (ECMO). Shunt fraction is the proportion of the ECMO pump flow which recirculates through the ECMO circuit (passing directly from the inflow cannula to the outflow cannula) instead of flowing through the pulmonary and systemic circulations. The indicator is an isotonic (150 mmol/l) solution of lithium chloride which is injected into the ECMO flow returning to the patient. Two lithium sensors are used simultaneously to record the resulting lithium dilution curves in arterial blood and in the blood in the ECMO circuit. Cardiac output and shunt fraction are derived from these curves. The techniques, which is simple and safe, provides measurements that allow optimal adjustment of ECMO flow and cardiovascular support.

Adolescent↗
PubMed1998

Minocycline-related autoimmune hepatitis: case series and literature review.

BACKGROUND: Minocycline is an antibiotic commonly used in the treatment of adolescent acne. OBJECTIVES: To describe the clinical, laboratory, and histological features in 3 cases of minocycline-related autoimmune hepatitis and to review the literature of similar cases in the adolescent population. DESIGN: Case series. SETTING: Patients were cared for in the Division of Gastroenterology, Children's Hospital, Boston, Mass. RESULTS: Three adolescents (age, 15-16 years), while being treated with therapeutic doses of minocycline for periods of 12 to 20 months, met the 1993 International Autoimmune Hepatitis Group criteria for autoimmune hepatitis. All had a positive antinuclear antibody titer. Other features included hypergammaglobulinemia and a positive anti-smooth muscle antibody titer. Two patients underwent liver biopsy that revealed severe chronic lymphoplasmacytic inflammation, necrosis, and fibrosis. All other causes of liver disease were excluded. One patient had resolution of symptoms with withdrawal of the drug, while 2 required immunosuppression therapy. A review of the literature yielded only 18 similar cases, none in the pediatric literature, the majority of which contained incomplete pertinent data. CONCLUSIONS: Minocycline is related to the development of autoimmune hepatitis in some adolescents. Pediatricians who use this drug for treatment of acne should be aware of this serious potential relation and stop the drug immediately when suspicion is raised.

Acne Vulgaris↗
PubMed1998

Histopathology of the liver in children with chronic hepatitis C viral infection.

Although the epidemiology, natural history, and pathological aspects of chronic hepatitis C are well-defined in the adult population, little is known about the characteristics of chronic hepatitis C infection in children. Reports on the histological features and progression of hepatitis C in children are scarce, and consist primarily of multicenter studies in Japanese and European children. Given the geographic variations in viral genotype and the association of pathology with genotype, whether the Japanese and European studies can be extended to the North American populations is unclear. We report the histopathology of the liver in 40 children with chronic hepatitis C infection treated in a single North American institution. The children included 19 males and 21 females ranging in age from 2.0 to 18.6 years at the time of liver biopsy (mean +/- SD: 11.4 +/- 4.3 years). Our findings indicate that the characteristic histopathological lesions of chronic hepatitis C infection, including sinusoidal lymphocytosis, steatosis, portal lymphoid aggregates/follicles, and bile duct epithelial damage, occur with approximately the same frequencies in children as have been reported in adults. Necroinflammatory activity was generally mild. Portal fibrosis was present in 78% of the specimens, including fibrous portal expansion (26%), bridging fibrosis (22%), bridging fibrosis with architectural distortion (22%), and cirrhosis (8%). Centrilobular pericellular fibrosis, which has not been previously reported in the context of chronic hepatitis C infection in adults or children, was also a prominent feature in our series, occurring with a similar frequency as steatosis or portal lymphoid aggregates/follicles. Our data suggest that in spite of mild histological necroinflammatory activity in general, the stage of fibrosis in children can be severe in spite of relatively short duration of infection.

Adolescent↗
PubMed1998

Drug-associated acute-onset vanishing bile duct and Stevens-Johnson syndromes in a child.

Acute vanishing bile duct syndrome is a rare but established cause of progressive cholestasis in adults, is most often drug or toxin related, and is of unknown pathogenesis. It has not been reported previously in children. Stevens-Johnson syndrome is a well-recognized immune complex-mediated hypersensitivity reaction that affects all age groups, is drug or infection induced, and has classic systemic, mucosal, and dermatologic manifestations. A previously healthy child who developed acute, severe, rapidly progressive vanishing bile duct syndrome shortly after Stevens-Johnson syndrome is described; this was temporally associated with ibuprofen use. Despite therapy with ursodeoxycholic acid, prednisone, and then tacrolimus, her cholestatic disease was unrelenting, with cirrhosis shown by biopsy 6 months after presentation. This case documents acute drug-related vanishing bile duct syndrome in the pediatric age group and suggests shared immune mechanisms in the pathogenesis of both Stevens-Johnson syndrome and vanishing bile duct syndrome.

Acute Disease↗
PubMed1998

Interferon-alpha treatment of chronic hepatitis C virus infection in children.

OBJECTIVES: To determine the safety and efficacy of interferon-alpha therapy of chronic hepatitis C virus (HCV) infection in children. STUDY DESIGN: This was an open-labeled prospective trial of interferon-alpha-2a (IFN-alpha) in children with evidence of HCV infection for at least 6 months. Twenty-three children were enrolled and treated with IFN-alpha at a dosage of 3 million units/m2 three times weekly. Beginning in 1995 patients defined as complete or partial responders after 6 months were offered an additional 6 months of treatment. Endpoints were alanine aminotransferase normalization and loss of hepatitis C viral ribonucleic acid from serum. Responders were compared with nonresponders for age, gender, duration of infection, pretreatment alanine aminotransferase and hepatitis C viral ribonucleic acid levels, saturation of serum iron-binding capacity, histologic score of chronic hepatitis and viral genotype. Statistical methods used for these comparisons included the Kruskal-Wallis test, the Mann-Whitney two-sample test and the Fisher exact test. RESULTS: Of the 21 children who completed at least 6 months of treatment, 4 (19%) had complete response, 8 (38%) had partial response and 9 (43%) had no response. Three of the 4 complete responders had prolonged treatment; in 2 the response was maintained. One responder relapsed but responded to a second, longer course of treatment. Four of the 8 partial responders had prolonged therapy and 3 of them became complete responders. One child who was originally a nonresponder lost HCV RNA within the first year after therapy. Thus eventually 7 (33%) of 21 patients were complete responders. After at least 12 months of follow-up on most of these children, no relapses have been observed. No differences in any of the variables tested could be demonstrated between responders and nonresponders, but small sample size limits power. IFN-alpha was discontinued in only one child because of side effects, and temporary dosage adjustments were needed in 4 children. CONCLUSIONS: IFN-alpha is of some efficacy in the treatment of chronic HCV infection in children. Complete or partial responders at 6 months should undergo prolonged treatment.

Adolescent↗
PubMed1998

Early onset of nephrotic syndrome after treatment with D-penicillamine in a patient with Wilson's disease.

Wilson's disease responds to a variety of treatments including D-penicillamine and trientene. Nephrotic syndrome is a late complication of D-penicillamine treatment. We report a pediatric patient with Wilson's disease who developed nephrotic syndrome 2 wk after beginning D-penicillamine. His nephrosis resolved and his disease is quiescent with trientene treatment.

Chelating Agents↗
PubMed1998

MR cholangiography in children after liver transplantation from living related donors.

OBJECTIVE: The purpose of this study is to report our technique for MR cholangiography in children and to describe the postoperative imaging findings in children who have undergone liver transplantation from living related donors. CONCLUSION: MR cholangiography can be used to delineate anatomy and morphology of the bile ducts of the left lateral segment graft in children who have undergone liver transplantation from living related donors. This information can guide treatment of postoperative biliary complications with interventional radiology or surgery.

Adolescent↗