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Biomedical subjects

K C Hyams

Publications and source records attributed to K C Hyams.

At least 91 records · Page 5Linked to original sources
PubMed1993

Comparative evaluation of six rapid serological tests for HIV-1 antibody.

Six commercial rapid test kits for HIV-1 antibody were evaluated. Four laboratory technologists tested sera from four groups of U.S. military personnel or dependents: 202 subjects positive for HIV-1 antibody by Western blot, 200 seronegative voluntary blood donors, 199 seronegative obstetrics/gynecology patients, and 99 subjects with sera reactive by ELISA but negative by recombinant protein EIA and indeterminate by Western blot. The three tests using solid-phase immunoassay technology demonstrated the highest mean sensitivity (> 99%) and specificity (> 91%) for all groups tested, including sera indeterminate by Western blot. Two dot-immunoblot assays were less specific, possibly due to indistinct reaction end points, and a latex agglutination assay was also less specific because of difficulty distinguishing reactive results from the granular background. In an "ease-of-use" assessment, solid-phase capture immunoassays required less time and equipment and were easier to interpret than other testing methods. Solid-phase capture immunoassays for HIV-1 antibody may be suitable for use in emergency situations and in developing countries because they are highly sensitive and specific and are rapidly performed with minimal laboratory equipment.

AIDS Serodiagnosis↗
PubMed1992

Human linear B-cell epitopes encoded by the hepatitis E virus include determinants in the RNA-dependent RNA polymerase.

Hepatitis E virus is responsible for both sporadic and epidemic hepatitis in developing countries. The nonenveloped virus is 27-34 nm in diameter and has been shown to contain a single-strand, positive-sense, polyadenylylated RNA genome of approximately 7.5 kilobases. The nucleotide sequence of the Burma strain of hepatitis E virus has been reported and three open reading frames (ORFs) have been identified. The deduced amino acid sequence from each of these ORFs was used to synthesize overlapping peptides (decamers overlapping at every fourth amino acid) on a solid phase. These peptides were then tested in an ELISA with pooled acute-phase sera from known cases of enterically transmitted non-A, non-B hepatitis collected in the Sudan. Linear B-cell epitopes were identified in all three ORFs. Epitopes were identified throughout the polyprotein encoded by ORF1, but they appeared to be particularly concentrated in the region of the RNA-dependent RNA polymerase. Distinct epitopes were identified in the presumed structural protein encoded by ORF2, and one epitope was identified close to the carboxyl terminus of the protein encoded by ORF3. These data precisely pinpoint linear B-cell epitopes recognized by antibodies from patients with acute hepatitis E and identify an antibody response directed against the RNA-dependent RNA polymerase.

Amino Acid Sequence↗
PubMed1992

Seroprevalence of hepatitis C antibody in Peru.

The prevalence in Peru of antibody to hepatitis C virus (anti-HCV) was determined in a survey of populations living in the northern jungle region and in groups at high risk of parenterally and sexually transmitted diseases. All sera were initially screened for anti-HCV using commercial first and second generation ELISAs; repeatedly reactive sera were further verified with a second generation immunoblot assay. Serum samples were also tested by ELISA for HBsAg, anti-HBs, and anti-HBc. None of 2,111 sera obtained in the survey of jungle residents was positive for anti-HCV by immunoblot assay. Twelve of 16 HIV-1 antibody positive hemophiliacs, one of 103 HIV-1 antibody positive homosexuals, and three of 602 HIV-1 negative registered female prostitutes were positive for anti-HCV. A high prevalence of total markers of hepatitis B infection was found in all subjects, especially in older subjects and groups at high risk of parenterally and sexually transmitted diseases. The findings of this study indicate that seropositivity for hepatitis C virus antibody is uncommon in Peru except in high risk groups and suggest that the epidemiology of hepatitis C differs substantially from hepatitis B.

Adolescent↗
PubMed1992

Acute sporadic hepatitis E in children living in Cairo, Egypt.

Seventy-three pediatric patients with acute hepatitis and 19 control patients without liver disease living in Cairo, Egypt, were evaluated with a newly developed Western blot assay for IgM antibody to hepatitis E virus (IgM anti-HEV). The mean age of acute hepatitis patients was 6.4 years (range, 1-13 years); 56% were male. Among the 73 acute cases, hepatitis A was diagnosed in 30 (41%), possible acute hepatitis B in three (4%), hepatitis E in nine (12%), and by exclusion, non-A, non-B hepatitis in 29 (40%). Two additional acute cases were positive for both IgM anti-HAV and IgM anti-HEV. None of the 19 control subjects had IgM anti-HEV. Parenteral risk factors were associated with cases of non-A, non-B hepatitis but were not associated with acute hepatitis E. Contact with a family member with jaundice was associated with acute hepatitis A. In contrast to prior epidemics of enterically-transmitted non-A, non-B hepatitis, HEV was found to be a common cause of acute hepatitis in a pediatric population. This study provides additional evidence that HEV may be a frequent cause of acute sporadic hepatitis among children living in some developing countries.

Adolescent↗
PubMed1992

Sexual transmission of human T-lymphotropic virus type I in Peruvian prostitutes.

The epidemiology of HTLV-I infection in female prostitutes was studied in a survey of 395 prostitutes from Callao, Peru (the port city of Lima), 72 prostitutes from Iquitos, Peru (another port city on the Amazon River), and 510 prenatal clinic patients from Lima. Prostitutes reported a mean of 8.8 years (range, 1-39 years) of active prostitution and a mean of 205 sexual contacts during the month prior to the study. The percentage of prostitutes with HTLV-I antibody (21.8%) was significantly higher than patients attending a prenatal clinic (3.1%; P less than .0001). The prevalence of HTLV-I antibody increased steadily with age in prostitutes, but no age trend was noted in prenatal patients. By multiple logistic regression analysis, an independent association was found between HTLV-I seropositivity and a history of prostitution in Callao, age, and positive syphilis serology when all 977 study subjects were evaluated. When prostitutes alone were analyzed, the number of years of exposure as a practicing prostitute was associated with HTLV-I seropositivity after controlling for age. These data indicate a greatly increased risk of HTLV-I infection in prostitutes in Callao, Peru, and suggest an association between sexual activity and HTLV-I transmission.

Adolescent↗
PubMed1992

Geographic risk factors for viral hepatitis and cytomegalovirus infection among United States Armed Forces blood donors.

In an effort to determine whether residence in a foreign country increases the risk of hepatitis B and C and cytomegalovirus (CMV) infection in United States (US) Armed Forces blood donors, 5719 volunteer donors at four US Navy blood banks were evaluated. Most participants were repeat donors (68%) and were young (mean age, 25 years), male (88%), and white (80%), black (10%), or Hispanic (7%). Birth outside of the United States was reported by 6 percent of subjects, and 34 percent had lived in a foreign country for more than 3 months. Twenty (0.3%) subjects had hepatitis B surface antigen (HBsAg), and 100 (1.7%) had antibody to hepatitis B core antigen (anti-HBc). Thirty-four (0.6%) were repeatably reactive in enzyme-linked immunosorbent assay for antibody to hepatitis C virus (anti-HCV); 11 (0.2%) had anti-HCV in immumoblot assay. Of the 3484 donors tested for anti-CMV, 1117 (32.1%) were positive. When demographic characteristics were controlled for both anti-HBc and anti-CMV seropositivies were independently associated in male blood donors with residence in the Philippines. Geographic factors were not associated with HBsAg and anti-HCV positivity. These findings indicate that the prevalence of serologic markers for viral hepatitis is low in military blood donors, but that residence in the Western Pacific is a risk factor for hepatitis B and CMV infection.

Adult↗
PubMed1992

Risk of viral hepatitis among military personnel assigned to US Navy ships.

A prevalence study of 2072 male US shipboard military personnel scheduled for deployment to South America/West Africa and the Mediterranean was conducted to determine whether serologic evidence of prior hepatitis A, B, or C infection is associated with exposure in foreign countries. There were 210 subjects (10.1%) who had antibodies to hepatitis A virus (anti-HAV), 76 (3.7%) to hepatitis B core antigen (anti-HBc), and 9 (0.4%) to hepatitis C virus (anti-HCV). By multivariate analysis, anti-HAV seropositivity was independently associated with age, non-white racial/ethnic groups, birth outside of the United States, and prior Caribbean deployment for less than 1 year. Anti-HBc seropositivity was independently associated with black and Filipino race/ethnicity, foreign birth, a history of a sexually transmitted disease, South Pacific/Indian Ocean deployment (less than 12 months), and South Pacific or Mediterranean duty for (greater than 1 year). No geographic risk factors were associated with anti-HCV positivity. These data indicate that military personnel deployed outside the United States are at increased risk of viral hepatitis infection and should be considered for vaccination.

Adult↗
PubMed1992

Acute sporadic hepatitis E in Sudanese children: analysis based on a new western blot assay.

A newly developed Western blot assay for antibody to hepatitis E virus (anti-HEV) was used to evaluate 39 cases of acute pediatric hepatitis and 39 control patients in Khartoum, Sudan. The mean age of cases was 6.5 years (range, 2-14); 64% were male. Acute hepatitis A (IgM anti-HAV-positive) was diagnosed in 13 cases, acute hepatitis B (IgM anti-HBc-positive) in 1, and acute hepatitis E (positive for IgM anti-HEV) in 23 (59%). None of the cases with IgM anti-HAV or IgM anti-HBc had IgM anti-HEV; 3 controls had IgM anti-HEV. Acute hepatitis E was associated with recent contact with a family member or acquaintance with jaundice and the presence of indoor plumbing. The newly developed hepatitis E assay appeared to be specific for the diagnosis of acute icteric non-A, non-B hepatitis. Hepatitis E was found to be the most common cause of acute sporadic hepatitis in children living in an urban area of Africa.

Acute Disease↗
PubMed1992

Oral erythromycin prophylaxis against Streptococcus pyogenes infection in penicillin-allergic military recruits: a randomized clinical trial.

Historically, military recruits have required benzathine penicillin G to prevent epidemics of Streptococcus pyogenes. In this randomized clinical trial, low-dose oral erythromycin was evaluated as an alternative for prophylaxis against group A beta-hemolytic streptococci in penicillin-allergic recruits. US Marine Corps recruits (186) reporting penicillin allergy were randomly given either oral erythromycin (250 mg twice a day) or a vitamin (one tablet daily) for 60 days. Evidence of infection was defined as a two-dilution rise in anti-streptolysin O titer. The erythromycin group had a significantly lower risk of S. pyogenes infection than did the vitamin group (relative risk 0.44; 95% confidence interval, 0.22-0.89). There was no significant difference among the treatment groups in isolation of group A beta-hemolytic streptococci from throat cultures. Low-dose oral erythromycin appears as effective as benzanthine penicillin G in preventing S. pyogenes infection.

Administration, Oral↗
PubMed1992

The epidemiology of hepatitis C virus antibody in Yemen.

A cross-sectional survey of 348 subjects without evidence of liver disease was conducted to investigate the prevalence and risk factors for hepatitis C virus antibody (anti-HCV) seropositivity in the Yemen Arab Republic. The mean age of study subjects was 28.7 years (range 3-80), and 61% were males. Using commercial enzyme-linked immunosorbent assays (ELISA), 6.0% (95% confidence interval [CI] 3.8-9.1) of subjects were anti-HCV-positive, 13.5% were hepatitis B surface antigen-positive (HBsAg-positive), and 51.4% were positive for at least one serologic marker of prior hepatitis B infection. Nine (2.6%; 95% CI 1.2-4.9) of the 21 ELISA-positive sera were confirmed to be anti-HCV positive by a recombinant immunoblot assay. Anti-HCV seropositivity was significantly associated with age (odds ratio [OR] 2.0 for each 10-year increase in age) and prior surgery (OR 10.1), but was not associated with a history of prior blood transfusion or markers of hepatitis B infection. These preliminary data suggest that hepatitis C may pose a substantial health threat in Yemen.

Adolescent↗
PubMed1992

Seroprevalence of hepatitis A, B, and C in a United States military recruit population.

One thousand five hundred thirty-eight U.S. Navy and Marine Corps enlisted recruits were tested for hepatitis A, B, and C serologic markers. The recruit population (mean age, 19 years) was 91% male, 69% white, 17% black, 9% Hispanic, 2% Filipino, and 2% "other" racial/ethnic group. Anti-HAV was found in 129 (8.4%) recruits, anti-HBc in 35 (2.3%), HBsAg in 5 (0.3%), and anti-HCV in 4 (0.3%). For recruits born in the U.S., the prevalence of anti-HAV and anti-HBc was 5.5% and 1.3%, respectively; for the 7% of recruits born outside the U.S., the prevalence was 44.9% and 14.0%, respectively. By logistic regression analysis, seropositivity for hepatitis A and B was independently associated with age, nonwhite racial/ethnic groups, and birth outside of the U.S. This study indicates that there is a relatively low risk of hepatitis A, B, and C infection among Navy and Marine Corps recruits.

Adolescent↗
PubMed1992

Upper respiratory disease in deployed U.S. Navy shipboard personnel.

A study was conducted to determine the risk of upper respiratory disease among deployed U.S. Navy shipboard personnel. Between January and June 1989, a Patient Encounter Form was used to collect disease information from 10 U.S. Navy ships. Patients with a diagnosis of upper respiratory infection (URI) on initial sick-call visit were used in this study. Information on time spent in various ports and time at sea for each of the 10 ships was also collected. A classification scheme was developed to permit daily estimates of URI rates and to indicate whether the ship was in port or at sea. Of 967 cases of URI, 64.4% occurred while at sea, with an average daily rate of 0.5/1,000 crew members; 35.4% of the cases occurred while in port, with an average daily rate of 0.4/1,000 crew members. There was an increase in URI rates after 9 days at sea or in port. These data suggest that there are defined periods of increased transmission of upper respiratory infections aboard ships, both at sea and in port.

Humans↗
PubMed1992

Norfloxacin compared to trimethoprim/sulfamethoxazole for the treatment of travelers' diarrhea among U.S. military personnel deployed to South America and West Africa.

A randomized treatment trial of travelers' diarrhea was carried out among U.S. military personnel participating in routine exercises in several port cities in South America and West Africa. A 5-day, twice daily course of either norfloxacin (400 mg) or trimethoprim/sulfamethoxazole (TMP/SMX, 160/800 mg) was given to 142 volunteers. At the end of 5 days of treatment, diarrhea had resolved in 100% of 73 patients receiving norfloxacin and 97.1% (67/69) receiving TMP/SMX. A probable bacterial pathogen was determined in 44% of 142 subjects: 49% of the norfloxacin group and 39% of the TMP/SMX group. The most common pathogens detected were enterotoxigenic Escherichia coli in 20% of cases and rotavirus in 15%. Resistance to TMP/SMX was present in 20 (27%) bacterial isolates, while no resistance to norfloxacin was found. Eight of 10 patients in the TMP/SMX treatment group who had TMP/SMX-resistant bacterial enteropathogens improved clinically. Both norfloxacin and TMP/SMX were clinically effective in the treatment of travelers' diarrhea in this military population.

Acute Disease↗
PubMed1991

Diarrheal disease during Operation Desert Shield.

BACKGROUND: Under combat conditions infectious disease can become a major threat to military forces. During Operation Desert Shield, there were numerous outbreaks of diarrhea among the U.S. forces. To evaluate the causes of and risk factors for diarrheal disease, we collected clinical and epidemiologic data from U.S. troops stationed in northeastern Saudi Arabia. METHODS: Between September and December 1990, stool cultures for enteric pathogens were obtained from 432 military personnel who presented with diarrhea, cramps, vomiting, or hematochezia. In addition, a questionnaire was administered to 2022 soldiers in U.S. military units located in various regions of Saudi Arabia. RESULTS: A bacterial enteric pathogen was identified in 49.5 percent of the troops with gastroenteritis. Enterotoxigenic Escherichia coli and Shigella sonnei were the most common bacterial pathogens. Of 125 E. coli infections, 39 percent were resistant to trimethoprim-sulfamethoxazole, 63 percent to tetracycline, and 48 percent to ampicillin. Of 113 shigella infections, 85 percent were resistant to trimethoprim-sulfamethoxazole, 68 percent to tetracycline, and 21 percent to ampicillin. All bacterial isolates were sensitive to norfloxacin and ciprofloxacin. After an average of two months in Saudi Arabia, 57 percent of the surveyed troops had at least one episode of diarrhea, and 20 percent reported that they were temporarily unable to carry out their duties because of diarrheal symptoms. Vomiting was infrequently reported as a primary symptom, but of 11 military personnel in whom vomiting was a major symptom, 9 (82 percent) had serologic evidence of infection with the Norwalk virus. CONCLUSIONS: Gastroenteritis caused by enterotoxigenic E. coli and shigella resistant to a number of drugs was a major problem that frequently interfered with the duties of U.S. troops during Operation Desert Shield.

Adolescent↗
PubMed1991

Hyperendemic Streptococcus pyogenes infection despite prophylaxis with penicillin G benzathine.

BACKGROUND: In closely confined populations, in which epidemics of Streptococcus pyogenes infection are common, penicillin G benzathine has long been used prophylactically to reduce morbidity from this pathogen. We report on our investigations of the effectiveness of penicillin G benzathine prophylaxis at a military recruit camp. METHODS: We prospectively studied the rates of pharyngeal colonization and infection by S. pyogenes among 736 male U.S. Marine Corps recruits from January through March 1989. Throat swabs for culture, clinical data, and questionnaire data were obtained during six examinations at intervals of two weeks. Serum samples obtained before training, after training, and from acutely ill recruits were analyzed with use of an antistreptolysin O microtitration technique. RESULTS: Although 93 percent of the recruits received prophylaxis with two intramuscular injections of 1.2 million units of penicillin G benzathine each (administered 30 to 39 days apart), 33 percent of the recruits were colonized by S. pyogenes, and 42 percent had infection (as defined by a two-dilution increase in the antistreptolysin O titer). Thirty-seven percent of 265 recruits who reported a sore throat and were infected with S. pyogenes did not seek medical attention. The recruits who were allergic to penicillin (7 percent of the total), who received no prophylaxis, were more likely to be colonized; an increased risk of colonization and infection among the nonallergic recruits was associated with the presence of a higher percentage of allergic recruits in the platoon. After the study was completed, all recruits who were allergic to penicillin were prescribed 250 mg of oral erythromycin twice daily (a total daily dose of 500 mg) for 60 days. Subsequently, the average weekly rate of clinically evident S. pyogenes pharyngitis fell by more than 75 percent. CONCLUSIONS: If the prevention of S. pyogenes infection is to be effective in closely confined populations such as military recruits, prophylactic antibiotics must be administered to all members of the population. Exempting those who are allergic to penicillin may create a bacterial reservoir from which infection can be transmitted to nonallergic members of the population.

Drug Hypersensitivity↗