Biomedical subjects

A Conrad

Publications and source records attributed to A Conrad.

At least 37 records · Page 2Linked to original sources

PubMed1999

Detection of de novo hepatitis C virus infection by polymerase chain reaction in hemodialysis patients.

Patients on chronic hemodialysis (HD) treatment have been identified by serological testing, including second- and third-generation enzyme-linked immunosorbent assay (ELISA), as a high-risk group for hepatitis C virus (HCV) infection. Previous studies have shown that de novo cases of HCV may occur in HD units in the absence of other parenteral exposures, which suggests the spread of HCV between patients. In addition, the reverse-transcription polymerase chain reaction (RT-PCR), which directly detects HCV virus, has identified HCV infection in chronic HD patients who are seronegative. The aim of this study was to determine the incidence of HCV infection detected by RT-PCR technology in a large cohort of chronic HD patients. One hundred and twenty chronic HD patients, HCV-negative by serological assays (second-generation ELISA) and molecular techniques (branched DNA and RT-PCR), were observed for a mean period of 9.5 months. They were tested monthly for serum alanine aminotransferase levels (ALT) and by second-generation ELISA. At the end of the follow-up period, they were again evaluated by branched DNA and RT-PCR testing. HCV RNA was detected in patients' sera by RT followed by PCR using two separate primer sets from the 5'-untranslated region of the HCV genome. Southern blot was performed using a digoxigenin-labeled probe. Two patients who had HCV RNA detectable by RT-PCR at the end of the follow-up period remained branched-DNA-negative. Thus, the incidence of de novo acquisition of HCV infection in the current investigation was 2.1% per year. In 1 patient RT-PCR positivity and anti-HCV ELISA seroconversion occurred. The 2nd patient remained anti-HCV ELISA-negative, although viremic. In both patients, the onset of positivity by RT-PCR was associated with a rise of ALT levels into the 'abnormal range' in our laboratory. In these 2 patients, de novo acquisition of HCV infection was observed in the absence of obvious parenteral risk factors other than their presence in the HD environment. In conclusion, de novo acquisition of HCV infection may be undetected by ELISA and branched-DNA assays. The need to monitor chronic HD patients by serial ALT testing is emphasized. RT-PCR should be incorporated into diagnostic testing for HCV infection in chronic HD patients. RT-PCR technology can identify HCV in HD individuals with raised ALT activity.

Alanine Transaminase↗

PubMed1999

Epidemiology and natural history of hepatitis G virus infection in chronic hemodialysis patients.

UNLABELLED: Patients on chronic hemodialysis (HD) have recently been identified as having a high prevalence of hepatitis G virus (HGV) infection. The clinical significance of HGV in this population remains unclear, with no data available as to the acquisition and natural history of HGV infection in this group. AIMS: To assess the prevalence and risk factors of HGV in a large cohort of chronic HD patients, and to evaluate the incidence and clinical consequences of HGV over time in this population. METHODS: Paired sera from 292 patients undergoing chronic HD treatment in four units in the Los Angeles area were tested for HGV RNA before and after they had been on HD for a mean period of 9.7 +/- 1.9 months. HGV was tested by a single-step RT-PCR using two couples of primers located in two different portions (5'UTR, NS5a) of the genome. The amplified products were detected by hybridization with 5' biotin-labeled probes specific for each region. RESULTS: At study entry there were 50 HGV RNA-positive patients, thus the HGV prevalence was 17% (50/292). The multivariate analysis by ordinal logistic regression model showed association (p = 0.0013) between HGV RNA and the location of patients among the HD units. No other significant associations were observed. Three (3/50 = 6%) HGV RNA-positive patients at study entry and 3 (3/41 = 7%) at the end of the follow-up showed a mild increase of alanine aminotransferase (ALT) activity in absence of other apparent causes of liver damage. 35 (70%) out of 50 HGV viremic patients had persistently detectable viremia during the study period; 15 (30%) had non-persistently detectable HGV RNA in the second serum specimen. There was no significant difference between the patients with persistently detectable HGV RNA and those who showed non-persistently detectable HGV viremia with regard to demographic, clinical or virological features. Six patients without detectable HGV viremia at the start of the study showed de novo HGV infection during the follow-up, thus the HGV incidence was 3.07% per year. These individuals did not simultaneously acquire HBV or HCV markers; de novo HGV infection was not associated with other demographic, clinical or virological features. One (16.7%) out of 6 individuals with HGV acquisition had persistently raised ALT levels and chronic HBsAg positivity. The prevalence of HGV was 14% (41/292) at the end of the observation period. CONCLUSIONS: The prevalence of HGV in our HD population was high; HGV positivity was strongly associated with the location of HD patients among the units; some HD individuals with current HGV infection showed biochemical signs of liver disease without other apparent causes. De novo acquisition of HGV occurred within HD units in the absence of evident parenteral risk factors for HGV other than their presence in the HD environment. A large portion of HGV viremic patients showed non-persistently detectable HGV viremia during the study. Acquisition of HGV was not associated with a rise in ALT activity unlike prior experience with de novo HCV in HD patients. Further investigations are warranted to explain the modes of HGV acquisition and the clinical significance of HGV in th HD population.

Chronic Disease↗

PubMed1999

Ultracentrifugation and concentration of a large volume of serum for HCV RNA during treatment may predict sustained and relapse response in chronic HCV infection.

The ability to predict accurately a sustained response during therapy in patients with hepatitis C virus (HCV) infection is unavailable. The aim of this study was to differentiate, during therapy, patients who would relapse from those with a sustained response by ultracentrifugation for residual serum HCV RNA. Sixty-one specimens (from 32 patients) collected during interferon therapy were assessed by ultracentrifugation. All were negative using a quantitative polymerase chain reaction (PCR) (detection limit < or = 100 copies/ml). One-milliliter aliquots were ultracentrifuged at 23,000 x g (160 min), and then the nucleic acid pellet was extracted, precipitated, and resuspended. Qualitative PCR was carried out in quadruplicate using two separate 5'UTR primer sets (8 results/specimen). A specimen was positive if > or = 1 gels was positive compared to controls. At weeks 12 and 24, 9/9 (100%) sustained response patients were negative by ultracentrifugation. In the 23 relapse patients at week 12, 7/12 specimens were positive; at week 24, 7/14 were positive. Earlier time points could not differentiate the patients' eventual response to therapy. The predictive value of a positive ultracentrifugation test for relapse at week 12 or 24 was 100%. The predictive value of a negative test for sustained response was 62% and 50% at week 12 and 24, respectively. These preliminary results indicate that patients with an eventual sustained response will have no detectable serum HCV RNA by week 12 or week 24. A positive result is 100% predictive of relapse.

Adult↗

PubMed1999

Trends in indications and outcomes in the Whipple procedure over a 40-year period.

There have been increasing changes in the role of pancreatoduodenectomy (PD) in the management of benign and malignant pancreatic disease. The aim of this paper was to compare the current role of PD with that of our earlier experience. The records of patients undergoing PD at our institution between 1983 and 1996 (Group A) were reviewed and compared with cases between 1956 and 1982 (Group B). Student's t test was used to analyze differences between groups. A total of 153 PDs were performed with 98 (64%) in Group A (88% of these in the last 6 years) and 55 (36%) in Group B. Carcinoma of the head of the pancreas was the most common indication for surgery in both periods (43% and 47% for Groups A and B, respectively). In Group A, the next most common indication was chronic pancreatitis, accounting for 28 per cent versus 13 per cent in Group B. Carcinoma of ampulla of Vater was also a common indication, making up 21 per cent of the cases in Group A and 20 per cent in Group B. Preoperative biliary drainage was performed in 62 per cent of Group A and 3 per cent of Group B patients (P < 0.001). Postoperative complications were comparable in both groups: delayed gastric emptying (22%), wound infection (17%), pancreatic fistula (13%), gastrointestinal bleeding (8%), and intestinal obstruction (3%). The perioperative mortality rate was significantly different between the two groups: 1 per cent in Group A versus 16 per cent in Group B (P < 0.001). Mean postoperative length of stay was 17 days in Group A (22 days for benign disease) and 25 days for Group B (P < 0.01). In the last 40 years, there has been a rise in the use of PD for chronic pancreatitis and a significant decrease in postoperative mortality and hospital length of stay. These data support the safety of PD in the management of patients with both benign and malignant periampullary disease.

Adult↗

PubMed1998

De novo hepatitis C in children after liver transplantation.

BACKGROUND: We describe the incidence, results of interferon therapy, and outcome of hepatitis C virus (HCV) hepatitis occurring de novo after pediatric orthotopic liver transplantation (OLT). METHODS AND RESULTS: Of children undergoing OLT between 1984 and September 1996, 321 children survived for more than 1 year. Of these, 13 (4.0%) developed previously undiagnosed HCV disease, as suggested by HCV antibody testing and HCV polymerase chain reaction and confirmed by liver biopsy. Of the 117 children who received transplants before HCV screening of blood products or donors, 10.2% developed de novo HCV disease. The mean age at diagnosis of HCV hepatitis was 13.2+/-5.0 years, and the mean time to diagnosis after OLT was 8.1 years (range, 4-11 years). The mean alanine aminotransferase (ALT) level at diagnosis was 108 IU/ml, and the liver biopsy specimen showed chronic active or chronic persistent hepatitis in 11 children, cirrhosis in 1 child, and nonspecific changes in 1 child. Twelve children were treated with interferon-2alpha; children who weighed > or =20 kg received 3 x 10(6) units every other day, and those who weighed <20 kg received 1.5 x 10(6) units every other day. Four patients developed rapidly progressive liver failure while receiving interferon therapy and required urgent re-transplantation. Three of the four children again developed histologic evidence of recurrent HCV 4-6 months after the second OLT, and all three subsequently died of HCV-induced liver failure. One patient remains alive and well with no evidence of HCV recurrence and a negative HCV RNA. Of the remaining eight children treated with interferon, only two have had a sustained response (normal ALT) and one is now HCV RNA negative. HCV RNA levels did not correlate with outcome or disease severity. HCV antibody levels were unreliable, with two patients having negative HCV antibody but a positive HCV RNA at diagnosis. Six patients were able to be genotyped: four were la and two were 1b. CONCLUSION: Overall mortality for de novo HCV hepatitis was 23%. Seventy-five percent of children who received a second transplant for HCV hepatitis had early histologic recurrence that led to liver failure and death. Interferon therapy resulted in a sustained improvement in ALT in only 15% of children. The time to onset and progression of clinical disease both in the original graft and the retransplant graft were accelerated compared with nonimmunosuppressed individuals.

Adolescent↗

PubMed1998

Is there an optimal time to measure quantitative HCV RNA to predict non-response following interferon treatment for chronic HCV infection?

BACKGROUND/AIMS: Current criteria to predict sustained response for a patient with chronic hepatitis C virus during interferon treatment are not consistent. The aim of this study was to determine a reliable point in time to predict non-response to therapy, as a theoretical basis for early cessation of treatment. METHODS: Sera (-70 degrees C) from 66 patients treated with interferon (3 million units three times a week for 6 months) were assayed with a quantitative polymerase chain reaction (sensitivity < or =100 copies per milliliter). Evaluations were made at baseline, during treatment at weeks 1, 2, 4, 12, and 24, and at follow-up week 48. Biochemical response was defined using standard alanine aminotransferase criteria. Virologic response was defined as: sustained if loss of HCV RNA persisted through therapy and follow-up; relapse if HCV RNA became undetectable but reappeared during treatment or follow-up; and non-response if HCV RNA remained detectable during the study period. Alanine aminotransferase and HCV RNA results were analyzed at defined time intervals to determine a predictive value for non-response and sustained response. RESULTS: HCV RNA results are a more accurate predictor than alanine aminotransferase for both non-response and sustained response. Serum HCV RNA predicted non-response better than sustained response. The optimal time to predict non-response with serum HCV RNA was treatment week 12. CONCLUSIONS: Treatment week 12 results indicate that HCV RNA was a more accurate predictor for non-response than serum alanine aminotransferase. This prediction would have theoretically permitted stopping treatment for 75% of the patients in this study at treatment week 12 allowing an overall cost savings of 28%.

Adult↗

PubMed1998

Long-term retreatment in chronic hepatitis C patients who were non-responders to an initial course of interferon-alpha 2b.

Nineteen patients with chronic hepatitis C who were virological non-responders (seven responder/relapse and 12 no response) to an initial 24-week course of interferon-alpha 2b (IFN-alpha 2b) at a dose of 3 million units (MU) thrice weekly were retreated for an additional 48 weeks at the same dosing schedule and followed-up for another 24 weeks post-therapy. At the end of follow-up (week 72), six (32%) of the 19 patients were hepatitis C virus (HCV) RNA negative and were virological complete responders to retreatment. The viral genotypes in these six patients included two each with 1b and 3a, one with 2b, and another with 2a/2b; five of the six virological responder patients had cirrhosis. Significant predictors for successful retreatment included lower baseline HCV RNA concentrations prior to the first course of therapy, 2 log10 reductions in serum HCV RNA during the initial treatment and classification into the virological 'responder/relapse' category after the first course of IFN (P < 0.01 for all observations). When the above factors were used to construct a predictive model to determine response to retreatment, it was found that the absence of a 2 log10 drop in HCV RNA concentrations during the first course of IFN therapy was the most reliable indicator of non-response to retreatment (likelihood ratio = 10, P = 0.0014). In addition, the presence of HCV RNA at week 12 of retreatment was 100% predictive of virological non-response to the 48-week course of therapy. Our findings indicate that an additional 48-week course of IFN-alpha 2b therapy at 3 MU thrice weekly will achieve a virological complete response in 60% of patients who had a 2 log10 drop in HCV RNA during their first course of treatment, and measurement of week-12 HCV RNA during retreatment to identify non-responders is beneficial to patients as well as being cost-effective. Thus, a second course of IFN remains a viable option in a subgroup of non-responder patients, regardless of genotype or the presence of compensated cirrhosis.

Adult↗

PubMed1998

Discordance between serum alanine aminotransferase (ALT) and virologic response to IFN-alpha2b in chronic hepatitis C patients with high and low pretreatment serum hepatitis C virus RNA titers.

Although serum alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA concentrations are primary markers used to assess the clinical benefit of interferon (IFN) therapy in patients with chronic HCV infection, discrepancies between these two variables exist. In this study, 103 patients with chronic hepatitis C were treated with 3 MIU IFN-alpha2b three times weekly for 24 weeks, followed by 24 weeks of observation. ALT and virologic responses were compared in patients with high pretreatment HCV RNA titers (defined as pretreatment HCV RNA concentrations at or above the 75th percentile of the distribution or >5,000,000 copies/ml) and low pretreatment HCV RNA titers (defined as pretreatment concentrations below the 75th percentile or < or =5,000,000 copies/ml). Analysis of the virologic response for the high-titer and low-titer groups demonstrated a significantly greater HCV RNA sustained response in the low-titer group (21%) compared with the high-titer group (7%) (p < 0.05). In contrast, the ALT sustained response was not significantly different between the low-titer group (21%) and the high-titer group (18%). Analysis of the correspondence between biochemical and virologic responses showed that only 38% of patients with high pretreatment HCV RNA titers had both a sustained ALT response and a sustained loss of HCV RNA compared with 75% of patients with low pretreatment HCV RNA titers. The level of agreement between the ALT and HCV RNA responses was greater for the low-titer group compared with the high-titer group (kappa = .6848 and kappa = .4966, respectively). Our results indicate that chronic HCV patients with high pretreatment HCV RNA titers showed greater discordance between sustained ALT and HCV RNA responses compared with patients with low pretreatment HCV RNA titers and that measurement of HCV RNA should be included in the assessment of response to IFN therapy in chronic hepatitis C patients.

Adult↗

PubMed1998

The changes in quantitative HCV RNA titers during interferon alpha 2B therapy in patients with chronic hepatitis C infection.

OBJECTIVE: Our aim was to analyze the outcomes and the patterns of response to interferon treatment in patients with chronic hepatitis C using serum HCV RNA as the primary endpoint of therapy. METHODS: Seventy anti-HCV-positive patients were treated with 3 million U of interferon-alpha-2b thrice weekly for 24 wk and followed for an additional 24 wk after cessation of therapy (wk 48). Serum HCV RNA was measured by a reverse transcriptase-polymerase chain reaction method that has a sensitivity of < 100 viral copies per ml. RESULTS: The mean pretreatment HCV RNA was 2.8 +/- 2.2 x 10(6) viral copies per ml. Genotype 1 patients had significantly higher mean baseline viral titers than those with genotype 2 (p = 0.03). At wk 48, 12 (17%) patients were HCV RNA negative and considered virological complete responders (CR) to treatment. The remaining patients were HCV RNA positive at wk 48 and were considered nonresponders to therapy. There were two types of virological nonresponder patients, responder relapse (RR) and no response (NR). The mean baseline HCV RNA level was significantly lower in the virological CR patients (p = 0.0004). At wk 12 and 24 of interferon treatment, both the virological CR and RR patients had lower serum HCV RNA concentrations than the patients in the NR category (p = 0.0001), while at wk 48, only. the virological CR patients had undetectable HCV RNA when compared to the RR and NR patients (p = 0.04). Transient decreases in the HCV RNA titers of > or = 1 log in magnitude were observed in 49% of the NR patients, which rose to pretreatment levels either during or after interferon therapy. CONCLUSIONS: Our findings indicate that measurement of serum HCV RNA precisely defined the responses to interferon therapy. Because the goal is to eliminate virus in patients with chronic hepatitis C infection, then HCV RNA should be used as the primary endpoint of treatment.

Adolescent↗

PubMed1997

Uptake of creatine phosphate into heart mitochondria: a leak in the creatine shuttle.

CrP uptake into isolated rat heart mitochondria was studied using silicone oil centrifugation. Further, the involvement of the mitochondrial adenine nucleotide translocase was examined by measuring CrP accumulation in mitochondria in the presence of substrates and inhibitors of the ATP/ADP-carrier and by investigating uptake kinetics in liposomes reconstituted with purified bovine heart adenine nucleotide translocase protein. CrP is accumulated in the matrix space of isolated rat heart mitochondria and mitoplasts. The uptake is inhibited by carboxyatractyloside, a specific inhibitor of the mitochondrial adenine nucleotide translocase, and by ADP, phosphoenolpyruvate, 3-phosphoglycerate and pyrophosphate, compounds which are able to bind to the carrier. It is not inhibited when the mitochondrial membrane potential is decreased. CrP is transported into reconstituted liposomes at a rate which is about 3 orders of magnitude lower than the rate for ATP uptake. The transport is sensitive to temperature change and to carboxyatractyloside. It is concluded that CrP is specifically taken up by heart mitochondria via the mitochondrial adenine nucleotide translocase. The transport in mitochondria in situ is facilitated by the close local and functional interaction of the mitochondrial creatine kinase and the adenine nucleotide translocase within contact sites between inner and outer mitochondrial membrane. A certain amount of CrP synthesized by the mitochondrial creatine kinase thus escapes its usage at cytosolic energy consuming processes.

Adenosine Diphosphate↗

PubMed1997

Prediction of response during interferon alfa 2b therapy in chronic hepatitis C patients using viral and biochemical characteristics: a comparison.

Patients with chronic hepatitis C (n = 103) were treated for 24 weeks with interferon alfa 2b and followed up for 24 weeks after cessation of therapy (week 48). When hepatitis C virus (HCV) RNA at week 48 was used to assess interferon response, 15 (14.6%) were virological complete responders, and all have remained HCV RNA negative for a mean of 3 years. At week 48, 3 of 15 virological complete responders had elevated alanine transaminase (ALT) values. When serum ALT level was used at week 48 to determine response to interferon, 20 (19.4%) were biochemical complete responders. However, 8 of the 20 patients with normal ALT levels were HCV RNA positive at week 48, and 7 of these individuals have had a recurrence of elevated ALT levels within 3 years after cessation of treatment. These findings indicate that measurement of HCV RNA was more accurate than ALT in determining true responses to interferon therapy. Identification of nonresponders early during the course of interferon treatment showed that an elevated ALT level at week 12 was 92% predictive (odds ratio 3.7) but misidentified 33% (5 of 15) of the patients who were virological complete responders at week 48. In contrast, a positive HCV RNA at week 12 of treatment was 98% predictive (odds ratio 35.5) and misidentified only 6.7% (1 of 15) of the virological complete responders. Thus, positive HCV RNA at week 12 of therapy was more accurate in identifying eventual virological nonresponders than measurement of ALT at this time. Termination of interferon therapy in patients who were HCV RNA positive at week 12 would result in a 27% reduction in the direct medical costs and keep patients from undergoing unnecessary treatment. Therefore, testing for HCV RNA at week 12 to identify nonresponders and then discontinuing their treatment is practical, cost-efficient and beneficial both to patients and to third-party payers.

Adolescent↗

PubMed1997

[Localized cowpox/cat pox virus infection. Aspects of epidemiology, diagnosis and therapy].

Only few human cowpox/catpox infections have been reported until now. The diagnosis of bland localized infections may be missed, if this disease is not well known. However, early diagnosis of localized cowpox/catpox infections is important, since at least immunocompromised patients are at risk of potential lethal generalization similar to generalized variola vera. Using a typical case report, the characteristics of the disease, as well as the current aspects of epidemiology, diagnosis and therapy are summarized. The characteristic finding of intracytoplasmatic inclusion bodies by light microscopy can be demonstrated in a human biopsy-specimen for the first time and greatly facilitated the diagnosis.

Animals↗

PubMed1997

The effects of lipopolysaccharide (LPS) on the fever response in rats at different ambient temperatures.

There is a complex interplay between the immune system, nervous system, and sleep. When an organism is challenged with lipopolysacchride (LPS), the immune system is stimulated, producing a fever response that is independent of ambient temperature, and an increase in slow-wave sleep (SWS). The study investigated sleep patterns of immune-challenged rats during the light phase cycle to determine the effects of various ambient temperatures. It was hypothesised that fever response would occur independently of ambient temperatures. Also, the febrile response would be monophasic, and there would be an increase in slow-wave sleep (SWS) and a decrease in rapid-eye-movement (REM) sleep. Thirty Wistar rats were randomly placed in 3 different ambient temperature groups, 22 degrees C, 15 degrees C, and 30 degrees C. Within each of these conditions, the same subjects served as control and experimental groups. Four animals were placed in 4 subsections of 2 standard boxes that were placed in the ambient-temperature box. The electrodes were connected to the analog to digital computer board, where all the data was processed and stored on a hard drive. The animals were injected I.P. with saline and recorded for a period of 6 h to establish a baseline. On Day 2, the same animals were injected I.P. with LPS and recorded for 6 h to determine the febrile effects of LPS on the immune system; the same procedure was repeated in the other ambient temperatures. The results have shown that animals experienced a monophasic fever response in low and normal temperatures, but not in the high temperatures. Although there was no increase in SWS, there was a significant decrease in REM sleep in 3 groups.

Animals↗

PubMed1996

Improved control of nausea and emesis with a new bromazepam-containing ondansetron regimen in ovarian cancer patients receiving chemotherapy with carboplatin and cyclophosphamide.

BACKGROUND: Ondansetron was found to be effective as an antiemetic in numerous clinical trials of highly emetogenic combination-chemotherapy regimens that included cisplatin. Its role in milder emetogenic regimes has not been fully defined. METHODS: This study investigated the efficacy of two different antiemetic regimes in thirty-five patients with ovarian cancer receiving 68 cycles of chemotherapy with carboplatin (350 mg/m2) and cyclophosphamide (600 mg/m2). Ondansetron (3 x 8 mg i.v.) was compared to a bromazepam-containing ondansetron regimen. RESULTS: Nausea was absent in 65% of chemotherapy courses in patients receiving the combination of ondansetron and bromazepam and in 38% of chemotherapy courses in patients receiving ondansetron alone. Complete control of emesis was achieved in 93% of the courses in patients receiving the combination and in 81% of the courses using ondansetron alone. CONCLUSIONS: The addition of bromazepam to ondansetron, and the extension of antiemetic prophylaxis to the day before and the day after chemotherapy improves the control of nausea and emesis compared to ondansetron monotherapy in patients with ovarian cancer.

Antiemetics↗

PubMed1995

In vitro determination of creatine kinase substrate fluxes using 31P-nuclear magnetic resonance.

Forward (kf) and reverse (kr) rate constants and the corresponding flux rates of the creatine kinase catalysed reaction between creatine phosphate (CrP) and adenosine triphosphate (ATP); CrP + ADP<-->kf kr ATP + Cr were measured in vitro at 295 K. Both rate constants were determined using magnetic resonance saturation transfer techniques. To study the dependence of kr and kf on the creatine kinase concentration, the creatine kinase activity was varied from 2400 to 75 U.ml-1. At equilibrium and high creatine kinase activities, the forward to reverse flux rate ratios are close to 1. A dispersion in the reaction rate constants was observed at activities < or = 600 U.ml-1. We measured kr > kf for all enzyme activities below 600 U.ml-1. This observation could partially be explained by the presence of ATPase contamination in the enzyme. These findings are relevant for the in vivo studies of creatine kinase activity in the presence of multi-site phosphate exchange in cellular ATP-pools. As mitochondrial creatine kinase is not in equilibrium these results are also of interest in this area.

Adenosine Triphosphate↗

PubMed1994

Clinical significance of concomitant hepatitis C infection in patients with alcoholic liver disease.

The significance of antibodies to hepatitis C virus in patients with chronic alcoholic liver disease is unclear. Prior studies have utilized the first-generation enzyme-linked immunosorbent assay, which is limited by problems with sensitivity and specificity. Hepatitis C virus infection in 137 patients with biopsy-proven alcoholic liver disease was assessed with second-generation hepatitis C virus antibody assays and reverse transcription-polymerase chain reaction for detection of hepatitis C virus RNA in the serum. The patients were categorized into three groups according to results of serological testing. Discriminant-function analysis was used to determine which factors (risk, biochemical and histological) could best differentiate the three groups. Thirty-three patients were reactive on second-generation enzyme-linked immunosorbent assay/second-generation recombinant immunoblot assay and RNA positive (group 1). Twelve were reactive on second-generation enzyme-linked immunosorbent assay/second-generation recombinant immunoblot assay but RNA negative (group 2). Eighty-six were nonreactive on second-generation enzyme-linked immunosorbent assay, and six were reactive on second-generation enzyme-linked immunosorbent assay but negative on second-generation recombinant immunoblot assay and negative for hepatitis C virus RNA (group 3). Seventy-six percent of patients in group 1 and 58% in group 2 had parenteral risk factors, compared with only 1% in group 3 (p < 0.00001). The mean ALT level was higher in group 1 patients (p < 0.05). The mean histologic activity index was significantly higher in group 1 (p = 0.0007).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Intrathecal IgG synthesis and albumin leakage are increased in subjects with HIV-1 neurologic disease.

We analyzed matched cerebrospinal fluid and blood samples from 139 subjects enrolled in a study of the effects of human immunodeficiency virus type 1 (HIV-1) on the nervous system. Mean total intrathecal IgG synthesis rate was significantly higher in subjects with HIV-1-related neurologic disease (NeuroPos) than in HIV-1-seropositive (HIV+) subjects without neurologic disease (NeuroNeg) or at-risk seronegative controls (SNC). Mean trans-blood-brain barrier (BBB) albumin leakage (AL) rate increased significantly across groups (SNC < NeuroNeg < NeuroPos). AL was significantly higher in subjects with absolute CD4 counts < 100/mm3 versus those with > or = 100 cells/mm3 and significantly higher in AIDS compared with asymptomatic HIV+. Elevated total intrathecal IgG synthesis rate could not be accounted for solely by the presence of a damaged BBB, because 79% of subjects with elevated IgG synthesis rates had a normal BBB as assessed by the AL formula. Furthermore, the Tourtellotte formula inherently corrects for BBB leakage. We confirmed, using state-of-the-art albumin and IgG determinations, that intrathecal IgG synthesis is prevalent in all stages of HIV-1 disease. In the absence of a CNS opportunistic infection or tumor, mean total intrathecal IgG synthesis rate and trans-BBB AL are significantly higher in subjects with clinical HIV-1 CNS disease than in neurologically normally HIV+ subjects.

Adult↗

PubMed1994

Quantifying HIV-1 proviral DNA using the polymerase chain reaction on cerebrospinal fluid and blood of seropositive individuals with and without neurologic abnormalities.

To quantify the number of human immunodeficiency virus type 1 (HIV-1) proviral copies per 1,000 CD4+ cells in cerebrospinal fluid (CSF) and blood in relationship to stage of infection and HIV-1 neurologic disease (HND), 87 HIV-1 seropositive men without CNS opportunistic infections, tumors, or neurosyphilis, 9 high-risk, and 14 not-at-risk seronegative controls underwent a structured interview, and physical and neurologic examination followed by blood and CSF collection. A custom-designed, fully automated polymerase chain reaction (PCR) system performed amplification with use of two HIV-1 gag primer pairs, Southern blotting, and hybridization with product-specific probes. Image analysis was used to quantify band intensities relative to a dilution series. Eighty-one of 87 (93%) seropositive patients, 1 of 9 high-risk patients, (11%) and none of 14 seronegative controls had PCR-detectable HIV-1 in their blood. Fifty-seven of 63 (90%) seropositive patients, 2 of 5 (40%) high-risk seronegative patients, and none of 14 controls had HIV-1 in their CSF. The proviral load in seropositive patients, all stages, was significantly greater in CSF than blood [median 25 vs. 0.6 copies/1,000 CD4+ cells (p = 0.0001)]. The median proviral load in blood was 0.09 copies/1,000 CD4+ cells in seropositive, asymptomatic subjects, 10.7 in patients with AIDS, and 1.4 in patients with AIDS-related complex (p = 0.0281). CSF proviral load was greater in seropositive patients with HND than those without HND, median 43.5 vs. 17.6 copies/1,000 CD4+ cells (p = 0.0614). Proviral load was greater in the blood and CSF of subjects with more advanced systemic disease and HND. There was a substantial penetration of HIV-1 into the CNS/CSF in both systemically and neurologically asymptomatic HIV-1 disease.

AIDS Dementia Complex↗