Milestones in the discovery of hepatitis C

The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis, prevention and cure of the disease. The combined work of three researchers, Alter H, Houghton M and Rice C, which set the basis for the diagnosis, treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents. This is a story of a transfusion-associated infection. A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis. That was followed by the identification of what was later known to be the hepatitis C virus (HCV) and the development of diagnostic tests. It all preceded the full molecular identification and demonstration of a causal effect. Finally it ended up with the development and discovery of a new class of therapeutic drugs, the direct acting antivirals, which are now used not only to cure the disease but most probably, to eliminate the problem. This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus. Finally, the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans.

Factors associated with tobacco, alcohol, and other drug use among youth living in West Central Mexico

AIM

To determine the prevalence of drug and substance abuse among high school students in Jalisco and its association with the severity of health, behavior and psychosocial problems in order to provide evidence for possible prevention and treatment needs.

METHODS

A multi-stage random sample of Jalisco high school students was given a paper-and-pencil survey based upon an adapted version of the drug use screening inventory (DUSI) (n = 24699; n = 2832). The DUSI showed adequate psychometric characteristics in this population. The statistical analyses accommodated the complex survey design with attention to unequal probability of selection and clustering of participants within schools and regions.

RESULTS

An estimated 44% of the students had smoked tobacco, one in five students was a current smoker, and one in four students used to smoke but had not smoked for one year or more. By contrast, 6.8% of the students reported having used marijuana, cocaine, or both. Behavioral problems, deviant peer affiliation, and troubled families were independently associated with drug use. One in two students who used tobacco or alcohol had used these drugs in the past year (46% and 54%, respectively), and one in four students who used marijuana or cocaine in their lifetime had used those drugs in the past year (28% in both cases).

CONCLUSION

The rates of cocaine use as well as the proportion of current users were higher than expected among high school students and indicate changing patterns of drug use in Mexico. These results corroborate that the general trend of drug use by youth in Mexico is increasing. Results from this study help us better understand the needs of at-risk youth and the need for new treatment and prevention strategies.

Protein tolerance to standard and high protein meals in patients with liver cirrhosis

AIM

To investigate the plasma amino acid response and tolerance to normal or high protein meals in patients with cirrhosis.

METHODS

The plasma amino acid response to a 20 g mixed protein meal was compared in 8 biopsy-proven compensated cirrhotic patients and 6 healthy subjects. In addition the response to a high protein meal (1 g/kg body weight) was studied in 6 decompensated biopsy-proven cirrhotics in order to evaluate their protein tolerance and the likelihood of developing hepatic encephalopathy (HE) following a porto-caval shunt procedure. To test for covert HE, the “number connection test” (NCT) was done on all patients, and an electroencephalogram was recorded in patients considered to be at Child-Pugh C stage.

RESULTS

The changes in plasma amino acids after a 20 g protein meal were similar in healthy subjects and in cirrhotics except for a significantly greater increase (P < 0.05) in isoleucine, leucine and tyrosine concentrations in the cirrhotics. The baseline branched chain amino acids/aromatic amino acids (BCAA/AAA) ratio was higher in the healthy persons and remained stable-but it decreased significantly after the meal in the cirrhotic group. After the high protein meal there was a marked increase in the levels of most amino acids, but only small changes occurred in the levels of taurine, citrulline, cysteine and histidine.The BCAA/AAA ratio was significantly higher 180 and 240 min after the meal. Slightly elevated basal plasma ammonia levels showed no particular pattern. Overt HE was not observed in any patients.

CONCLUSION

Patients with stable liver disease tolerate natural mixed meals with a standard protein content. The response to a high protein meal in decompensated cirrhotics suggests accumulation of some amino acids but it did not precipitate HE. These results support current nutritional guidelines that recommend a protein intake of 1.2-1.5 g/kg body weight/day for patients with cirrhosis.

Non-injection drug use and hepatitis C among drug treatment clients in west central Mexico

BACKGROUND

Research on hepatitis C virus (HCV) prevalence among non-injecting drug treatment clients in the United States, Europe and Asia indicate substantial differences by place. To date, little or no research on HCV and non-injection drug use (NIDU) has been conducted in Mexico.

METHODS

We examined the prevalence of HCV, hepatitis B virus (HBV), and HIV among non-injecting drug users (NIDUs) in community-based drug treatment (N=122) and NIDUs in a prison-based drug treatment program (N=30), both located in west central Mexico.

RESULTS

Among the community clients, prevalence was 4.1% (95% confidence interval [CI]: 1.8-9.2) for HCV, 5.7% for HBV (95% CI: 2.8-11.4), and 1.6% for HIV (95% CI: 0.4-5.8). Among the in-prison clients, prevalence was 40.0% (95% CI: 24.6-57.7) for HCV, 20.0% for HBV (95% CI: 9.5-37.3), and 6.7% for HIV (95% CI: 1.9-21.3). None of the clients were aware of being infected.

CONCLUSION

The HCV prevalence found for the NIDU community treatment clients ranks among the lower HCV estimates published for NIDUs in treatment to date. The prevalence found for the in-prison clients ranks among the higher, raising a concern of possible elevated HCV infection among NIDUs in the west central Mexico prison--one compounded by the finding that none of this study's clients knew they were HCV positive.