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Biomedical subjects

J L Sanchez

Publications and source records attributed to J L Sanchez.

70 records · Page 4Linked to original sources
PubMed1984

An efficacy trial of doxycycline chemoprophylaxis against leptospirosis.

Because leptospirosis has been an important cause of morbidity in U.S. soldiers training in the Republic of Panama, we conducted a randomized, double-blind, placebo-controlled field trial during the fall of 1982 to determine whether doxycycline was an effective chemoprophylactic agent against this infection. Doxycycline (200 mg) or placebo was administered orally on a weekly basis and at the completion of training to 940 volunteers from two U.S. Army units deployed in Panama for approximately three weeks of jungle training. Twenty cases of leptospirosis occurred in the placebo group (an attack rate of 4.2 per cent), as compared with only one case in the doxycycline group (attack rate, 0.2 per cent, P less than 0.001), yielding an efficacy of 95.0 per cent. This study demonstrated the value of doxycycline as a prophylactic drug against leptospirosis.

Clinical Trials as Topic↗
PubMed1984

Behavior of melanocytic nevi during pregnancy.

Three hundred eighty-nine pregnant women were interviewed and examined for the purpose of determining the incidence and quality of changes that may have occurred in their pigmented cutaneous lesions during their pregnancies. Somewhat more than 10% of them reported changes had occurred in their pigmented lesions, most in the first trimester of pregnancy. However, in 26 lesions that had been biopsied, no significant histologic changes were found when compared with comparable pigmented lesions from age-matched women who were not pregnant.

Adolescent↗
PubMed1983

Collagenous papules on the aural conchae.

Four cases of a new entity characterized by papules that are smooth in surface and unchanged in color on the aural conchae are reported. Histologically they are characterized by sclerotic and hyalinized masses within thickened dermis and by special stains and electron microscopy are revealed to consist of altered collagen.

Adult↗
PubMed1981

Melasma: a clinical, light microscopic, ultrastructural, and immunofluorescence study.

Melasma is an acquired brown hypermelanosis of the face. Although it is thought that melasma is associated with multiple etiologic factors (pregnancy, gastric, racial, and endocrine), one of the primary causes of its exacerbation appears to be exposure to sunlight. Three patterns of melasma are recognized clinically: (1) a centrofacial pattern, (2) a malar pattern, and (3) a mandibular pattern. Examination of patients with Wood's light (320--400 nm) is useful in classifying the specific type of melasma in correlation with the localization of pigment granules (melanosomes) in the epidermis and dermis. Four types of melasma are described on the basis of Wood's light examination: (1) an epidermal type, (2) a dermal type, (3) a mixed type, and (4) a fourth type, described in patients of dark complexion, in which the lesions, for lack of contrast, are not discernible on Wood's light examination, perhaps due to the increased number of melanosomes in the normal skin of black individuals. Light, histochemical, and electron microscopic studies revealed an increase in number and activity of type-specific melanocytes which appeared to be engaged in increased formation, melanization, and transfer of pigment granules (melanosomes) to the epidermis as well as to the dermis. The melanocyte seems to undergo a functional alteration brought about by a combination of multiple factors, including persistent sun exposure, hormonal factors, and genetic predisposition.

Adult↗
PubMed1979

An adjustable sterile lead apron for radiation protection during angiography.

A simple sterile lead apron can be mounted directly on any vertical-beam image-intensifier housing and readjusted by the angiographer to shield himself from scatter during fluoroscopy and cineangiocardiography, even if the image intensifier is titled in the longitudinal plane. Properly placed, the apron effectively reduces exposed due to scatter.

Angiography↗
PubMed1979

The patch stage of mycosis fungoides. Criteria for histologic diagnosis.

It has long been claimed that a specific histologic diagnosis of mycosis fungoides cannot be made in the premycotic" or "eczematous" (patch) stage of the disease. Indeed, the histologic features of the premycotic lesions were constantly said to be those of "chronic non-specific dermatitis." We studied 46 biopsy specimens of patch lesions from patients in whom mycosis fungoides was unequivocally established by clinical events (i.e., concurrence or later development of typical plaque and/or nodular lesions) and indubitable histologic findings. We divided patch lesions into early nonatrophic patches and late atrophic ones. The early patches are considered to be evolving lesions of mycosis fungoides, whereas late patches represent resolving plaques of the disease. On the basis of this study, we concluded that histologic diagnosis can be made with near certainty in patch lesions of the disease. We found that the critical feature for histologic diagnosis of early and late patch lesions of mycosis fungoides is the presence of an increased number of mononuclear cells distributed singly or in small collections within an epidermis devoid of spongiotic microvesiculation. Other important features are lacunae surrounding intraepidermal mononuclear cells which gives them the appearance of "haloed cells." A sparse infiltrate of mononuclear cells is present around the blood vessels of the superficial, and sometimes the deep, vascular plexus. Atypical mononuclear cells are not necessary for the diagnosis of early patch lesions of mycosis fungoides, but they are found commonly in late patch lesions. Late atrophic patches show a thinned epidermis, loss of the usual configuration between rete ridges and dermal papillae, and coarse collagen throughout a thickened papillary dermis.

Adolescent↗
PubMedDate not supplied

A cluster of tick-borne infections: association with military training and asymptomatic infections due to Rickettsia rickettsii.

During the spring of 1989, 86 members of a military unit from the state of Maryland, USA, participated in two-week-long training manoeuvres in the states of Arkansas (location FC) and Virginia (location FAPH). Acute febrile illnesses due to infections with two tick-borne pathogens, Rickettsia rickettsii and Ehrlichia sp., were confirmed serologically in 2 initial cases who were admitted to the hospital. A seroepidemiological investigation among unit members found an additional 17 of 109 individuals (16%) with elevated post-exposure indirect immunofluorescent antibody (IFA) titres to R. rickettsii (16 cases) and/or E. canis (2 cases). The seropositivity rate of personnel who trained at FC was 38% (15 of 40), compared to only 13% (4 of 31) and 8% (3 of 38) of personnel who trained at FAPH or who did not train in the field, respectively (P < 0.001). Seropositivity was associated with symptoms suggestive of a tick-borne illness. Only 4 (22%) and 6 (33%) of the 18 personnel seropositive for R. rickettsii reported an erythematous or petechial type of rash or a febrile illness, respectively, within 4 weeks of exposure; 5 of 18 (28%) personnel infected with R. rickettsii reported no symptoms and only 8 of 18 (44%) received medical treatment. Mild infections with R. rickettsii, or a closely related spotted fever group agent, may have accounted for the high infection rate experienced by this group.

Antibodies, Bacterial↗
PubMedDate not supplied

Short course albendazole treatment for neurocysticercosis in Columbia.

The efficacy of albendazole was evaluated in 20 Colombian patients with neurocysticercosis showing neurological symptoms. All had parenchymal non-enhancing cystic images by computerized tomography and a positive enzyme-linked immunosorbent assay for cysticercus antibodies in serum or cerebrospinal fluid. They stayed in hospital for 8 d during treatment with albendazole, 15 mg/kg/d in 2 divided doses, and were then followed for at least 6 months after treatment. The number of cysts was reduced by 50% after 6 months. In 7 (35%) all cysts disappeared, in 7 (35%) the number was reduced, and in the remaining 6 (30%) the number was unchanged. In the 13 patients who still had cysts at 6 months, 11 showed a moderate decrease in average cyst size and in 2 the size was unchanged. Side effects during treatment were observed in 60% of the cases, but only 3 required corticosteroids.

Adolescent↗
PubMedDate not supplied

Immunological response to Vibrio cholerae O1 infection and an oral cholera vaccine among Peruvians.

A 'double-blind', randomized, placebo controlled study of an oral inactivated whole cell plus recombinant B subunit (WC/rBS) cholera vaccine was conducted during February-March 1992 in Peru in 346 military recruits, 307 (89%) of whom received 2 oral doses of vaccine or Escherichia coli K12 placebo, 2 weeks apart. Paired serum samples were obtained from 155 (50%) of the recipients of 2 doses. An epidemic of cholera took place between doses. No difference in cholera attack rates was detected between vaccine and placebo recipients after one dose (8% versus 14%). Seroconversion (4-fold or higher increase in vibriocidal antibody titres) was detected in 90% and 80% of vaccine and placebo recipients, respectively, with low pre-existing vibriocidal titres (< 0.01). The anti-cholera toxin seroconversion rate among those with low pre-existing titres was higher in vaccinated subjects (97%) than in placebo recipients (68%) (P < 0.01). Administration of 2 doses of WC/rBS vaccine concomitantly with natural V. cholerae O1 infection enhanced the serum anti-cholera toxin response. The immune response to the whole cell component of the vaccine was reduced by high pre-existing vibriocidal antibody titres.

Adolescent↗
PubMedDate not supplied

Malaria in Brazilian military personnel deployed to Angola.

BACKGROUND: Malaria represents one of the most important infectious disease threats to deployed military forces; most personnel from developed countries are nonimmune personnel and are at high risk of infection and clinical malaria. This is especially true for forces deployed to highly-endemic areas in Africa and Southeast Asia where drug-resistant malaria is common. METHODS: We conducted an outbreak investigation of malaria cases in Angola where a total of 439 nonimmune Brazilian troops were deployed for a 6-month period in 1995-1996. A post-travel medical evaluation was also performed on 338 (77%) of the 439 soldiers upon return to Brazil. Questionnaire, medical record, thick/thin smear, and serum anti-Plasmodium falciparum antibody titer (by IFA) data were obtained. Peak serum mefloquine (M) and methylmefloquine (MM) metabolite levels were measured in a subsample of 66 soldiers (42 cases, 24 nonmalaria controls) who were taking weekly mefloquine prophylaxis (250 mg). RESULTS: Seventy-eight cases of malaria occurred among the 439 personnel initially interviewed in Angola (attack rate = 18%). Four soldiers were hospitalized, and 3 subsequently died of cerebral malaria. Upon return to Brazil, 63 (19%) of 338 soldiers evaluated were documented to have had clinical symptoms and a diagnosis of malaria while in Angola. In addition, 37 (11%) asymptomatically infected individuals were detected upon return (< 1% parasitemia). Elevated, post-travel anti-P. falciparum IFA titers (> or = 1:64) were seen in 101 (35%) of 292 soldiers tested, and was associated with a prior history of malaria in-country (OR = 3.67, 95% CI 1.98-6.82, p <.001). Noncompliance with weekly mefloquine prophylaxis (250 mg) was associated with a malaria diagnosis in Angola (OR = 3.75, 95% CI 0.97-17.41, p =.03) but not with recent P. falciparum infection (by IFA titer). Mean peak levels (and ratios) of serum M and MM were also found to be lower in those who gave a history of malaria while in Angola. CONCLUSIONS: Malaria was a significant cause of morbidity among Brazilian Army military personnel deployed to Angola. Mefloquine prophylaxis appeared to protect soldiers from clinical, but not subclinical, P. falciparum infections. Mefloquine noncompliance and an erratic chemoprophylaxis prevention policy contributed to this large outbreak in nonimmune personnel. This report highlights the pressing need for development of newer, more efficacious and practical, prophylactic drug regimens that will reduce the malaria threat to military forces and travelers.

Angola↗
PubMedDate not supplied

Hepatitis C in Peru: risk factors for infection, potential iatrogenic transmission, and genotype distribution.

A large seroepidemiologic and genotyping study of hepatitis C virus (HCV) was conducted in Lima, Peru, during the periods of 1986 to 1993 (cohort A) and 1994 (cohort B). Anti-HCV seroprevalence rates were 15.6% (216 of 1,389) and 11.7% (168 of 1,438), respectively. Low rates were seen among volunteer blood donors (1.1% and 0.8%). Anti-HCV rates were much higher among patients undergoing hemodialysis (43.7% and 59.3%), hemophiliacs (60.0% and 83.3%), in those more than 39 years old (18.2% and 26.0%), in females (25.0% and 27.4%), and in less-educated persons (16.9%). Age- and gender-adjusted risk factors in cohort B included blood transfusion history (adjusted odds ratio [AOR] = 29.8), prior organ transplantation (AOR = 9.1) or a history of hepatitis (AOR = 4.9), previous hospitalization (AOR = 3.7), a history of intravenous drug use (AOR = 3.5), prior major surgery (AOR = 2.6), a history of acupuncture (AOR = 2.1), previous dental procedures (AOR = 1.2), and prior medical injections (AOR = 1.04). The most prevalent HCV genotype was type 1 (86%), followed by type 3 (10%) and type 2 (2%). Transmission through unsafe injection-related and medical/dental procedures appears to play an important role in HCV infection among Peruvians.

Adolescent↗