Biomedical subjects

L S Garcia

Publications and source records attributed to L S Garcia.

At least 19 recordsLinked to original sources

PubMed1994

Detection of microsporidial spores in fecal specimens from patients diagnosed with cryptosporidiosis.

Patients infected with Cryptosporidium parvum may have concurrent infections with microsporidia. Two modified trichrome stains and a polyclonal indirect fluorescent-antibody procedure were used for the detection of microsporidia; the Merifluor Cryptosporidium-Giardia monoclonal direct immunofluorescence detection kit was used for the detection of C. parvum. Formalinized stool specimens from 60 immunocompromised patients strongly suspected of having or previously diagnosed with cryptosporidiosis or microsporidiosis were examined. All patients were positive for one or both parasites, 18 (30%) with C. parvum only, 25 (42%) with microsporidia only, and 17 (28%) with both C. parvum and microsporidia. These findings emphasize the importance of considering both organisms as potential causative agents of diarrhea in compromised patients.

Animals↗

PubMed1993

Evaluation of intestinal protozoan morphology in polyvinyl alcohol preservative: comparison of zinc sulfate- and mercuric chloride-based compounds for use in Schaudinn's fixative.

As a result of disposal problems related to the use of mercury compounds, many laboratories have considered switching from mercuric chloride-based Schaudinn's and polyvinyl alcohol (PVA) stool preservatives to other non-mercury-based preservatives. The primary use for PVA-preserved specimens is the permanent stained smear, the most important technique in the routine ova and parasite examination for the identification and confirmation of intestinal protozoa. A comparison of organism recovery and morphology of the intestinal protozoa was undertaken with PVA containing either a zinc sulfate base or the "gold standard" mercuric chloride base. Paired positive fecal specimens (106 from 64 patients) were collected and examined microscopically by the trichrome stain technique. There were 161 instances in which organism trophozoite and/or cyst stages were identified and 3 in which human cells were identified. Morphology, clarity of nuclear and cytoplasmic detail, overall color differences, and the ease or difficulty in detecting intestinal protozoa in fecal debris, as well as the number of patients with a missed diagnosis, were assessed from the permanent stained smear. Overall organism morphology of the intestinal protozoa preserved in zinc sulfate-PVA was not always equal in nuclear and cytoplasmic detail or range of color after permanent staining to that seen with mercuric chloride-PVA. However, the same organisms were usually identified in both specimens, with the exception of situations in which organism numbers were characterized as rare (no organisms per 10 oil immersion fields at x1,000 magnification but at least one organism in the smear) [9 of 161 (5.6%)] or the organism was missed because of poor morphologic detail [12 of 161 (7.5%)]. In only six of these cases [6 of 161 (3.7%)] did the results involve pathogens. The patient diagnosis was missed in four cases of amebiasis and two cases of giardiasis; in both situations the organism numbers were rare. There were no discrepant results with Dientamoeba fragilis. Overall agreement between the two PVA-based results was 87.0% (140 of 161); when the instances of rare organisms were disregarded, the overall agreement was 92.5% (149 of 161). On the basis of these findings, zinc-PVA is viable substitute for mercuric chloride-PVA used for trichrome permanent stained smears.

Animals↗

PubMed1992

Evaluation of a new monoclonal antibody combination reagent for direct fluorescence detection of Giardia cysts and Cryptosporidium oocysts in human fecal specimens.

Giardia lamblia and Cryptosporidium parvum can cause severe symptoms in humans, particularly in the immunologically compromised. Monoclonal antibody reagents offer increased sensitivity and an excellent alternative to conventional staining methods. These reagents are helpful when screening large numbers of patients or those with minimal symptoms. Problems of false-positive and false-negative results with routine staining methods for stool parasites can be eliminated with monoclonal antibody reagents. Known positive formalinized specimens [Giardia sp. (n = 60), Cryptosporidium sp. (n = 55), and mixed Giardia-Cryptosporidium spp. (n = 10)] and negative formalinized specimens (n = 105), of which 46 contained other yeast or human cells or protozoa), were tested by the MERIFLUOR Cryptosporidium-Giardia direct immunofluorescence detection procedure. The MERIFLUOR reagent exhibited +/- to 4+ (majority, 2+ to 3+) on all Giardia cysts and 2+ to 4+ (majority, 3+ to 4+) on all Cryptosporidium oocysts. The cysts were generally oval (11 to 15 microns), while the oocysts were round (4 to 6 microns); both showed apple-green fluorescence against a background free of nonspecific fluorescence. All specimens positive for Giardia sp. and/or Cryptosporidium sp. showed fluorescence, and all specimens negative for the two organisms showed no fluorescence. There were eight specimens previously negative by the ova and parasite examination which were positive by the direct fluorescence method; four contained Giardia sp., and four contained Cryptosporidium sp. These positive results were confirmed after the examination of additional trichrome and modified acid-fast smears. The MERIFLUOR reagent was very easy to use, and even with a lower fluorescence intensity for Giardia sp. cysts, no false-negative or false-positive results among the specimens tested for either organism were found.

Animals↗

PubMed1991

Cryptosporidiosis.

Before 1982, only eight case reports of human cryptosporidiosis and fewer than 30 papers on Cryptosporidium spp. appeared in the biomedical literature. At that time, cryptosporidiosis was thought to be an infrequent infection in animals and rarely an opportunistic infection in humans. The concept of Cryptosporidium spp. as pathogens has changed dramatically within the past 8 years because of improved diagnostic techniques, increased awareness within the biomedical community, and the development of basic research programs in numerous laboratories. Presently, greater than 1,000 publications including over 400 case reports in the biomedical literature address Cryptosporidium spp. and cryptosporidiosis. Cryptosporidium parvum is now thought to be one of the three most common enteropathogens causing diarrheal illness in humans worldwide, especially in developing countries. It is likely that cryptosporidiosis was previously included in the 25 to 35% of diarrheal illness with unknown etiology. Because of the severity and length of diarrheal illness and because no effective therapy has been identified, cryptosporidiosis is one of the most ominous infections associated with AIDS. The role of C. parvum as an enteropathogen is well established; documentation of its role as a cause of hepatobiliary and respiratory diseases is now appearing in the literature. Our present understanding of the natural history, epidemiology, biology, and immunology of Cryptosporidium spp. as well as the clinical features, pathogenicity, and treatment of cryptosporidiosis are reviewed here.

Animals↗

PubMed1991

Cryptosporidiosis.

Data suggest that C. parvum is now one of the three most commonly found enteropathogens causing diarrheal illness in humans worldwide. This article discusses the etiologic agents, epidemiology, clinical features, diagnosis, and treatment of cryptosporidiosis. To date, no effective therapy for cryptosporidiosis has been identified.

Acquired Immunodeficiency Syndrome↗

PubMed1990

[Changes in body fluids of the frog Leptodactylus fuscus during estivation (Anura, Leptodactylidae)].

The frog, L. fuscus, becomes dormant during the dry season in southeastern Brazil. Plasma and urine were obtained and analyzed for K+, Na+, and osmotic concentrations in active and estivating frogs. Soil water potential from the estivation sites was compared with the osmotic concentrations of the frog. Plasma and urine osmotic concentrations (286.2 +/- 13.8 and 242.3 +/- 17.2 mOsm1(-1), respectively) were higher in the estivating than in active frogs (240.3 +/- 12.8 and 112.7 +/- 15.6 mOsm1(-1); plasma and urine), and the same holds true for plasma K+ content. The Na+ concentration was the same for active and estivating frogs. Soil water potential corresponded to osmotic pressure of 110 mOsm1(-1), showing that L. fuscus may uptake water from the soil during the estivation.

Animals↗

PubMed1989

Cryptosporidiosis: clinical features and diagnosis.

Cryptosporidiosis is an infectious disease caused by the coccidian parasite Cryptosporidium spp. that primarily infects the gastrointestinal tract of animals. Prior to late 1982, only 11 cases of human infection had been reported, with the first human case reported in 1976. During the 1980s, the number of human cases began to rise dramatically. Most of these patients were immunodeficient, many of whom had the acquired immune deficiency syndrome (AIDS). Immunocompetent individuals can also acquire the infection with mild-to-severe diarrhea lasting from several days to weeks. Immunocompromised patients develop severe, irreversible diarrhea, often thought to be a significant contributing factor leading to death. Although many therapeutic compounds have been tried, none have proven to be very successful. The incidence of this infection is worldwide, with many published reports of infection in both immunodeficient and immunocompetent individuals. The diagnostic approach has been expanded to include stool examinations using modified acid fast procedures and fluorescent monoclonal antibody reagents. Although histological methods are still routinely used for biopsy specimens, the examination of stool has proven to be a very effective, noninvasive procedure. In addition to the gastrointestinal tract, other areas of the body that have been found to be infected with this organism include the respiratory tract and the biliary tree and gall bladder epithelium. Screening for this organism may become very important in known risk groups (animal handlers; children, staff members, and contacts of those who attend day care centers; travelers; and those who are immunodeficient), particularly if an effective therapy is found. Some laboratories screen every specimen submitted for an ova and parasite examination, while others have limited their testing to specific requests, risk groups, and those patients who are symptomatic.

Animals↗

PubMed1988

Incidence of Cryptosporidium in all patients submitting stool specimens for ova and parasite examination: monoclonal antibody IFA method.

The development of a monoclonal antibody to Cryptosporidium oocysts provides a more sensitive detection method than that seen using other diagnostic techniques. Incidence reports on this organism have been based on earlier, less-sensitive methods. In order to determine the numbers of positive patients and stool specimens, every stool specimen submitted for an ova and parasite examination was tested using the Merifluor IFA system (Meridian Diagnostics, Inc). Over a 12-mo period, 2,786 specimens were tested (1,516 patients). Positive specimens (23) were from nine known immunosuppressed patients and from four symptomatic immunocompetent patients. This represents an overall positive rate of 0.86% (patients). In those patients who were not suspected of having cryptosporidiosis (immunocompetent), diagnosis of this infection would not have been accomplished without the use of a sensitive screening method. This data, obtained over a 12-mo period, provides information for those laboratories considering the clinical relevance of screening all stool specimens for this infection. With the development of therapy, early detection of Cryptosporidium will become more important.

Animals↗

PubMed1987

Fluorescence detection of Cryptosporidium oocysts in human fecal specimens by using monoclonal antibodies.

With the discovery that the coccidian parasite Cryptosporidium sp. can cause severe symptoms in humans, implementation of many diagnostic techniques rapidly followed. The infection is self-limiting in patients with normal immune systems but chronic in the immunosuppressed patient. With the eventual development and use of therapeutic agents, it will become very important to find Cryptosporidium sp., even in low numbers, in fecal specimens. Production of a highly specific and sensitive antibody by use of cloning techniques has provided another diagnostic tool. Formalinized positive human fecal specimens (n = 99) and negative specimens (n = 198), of which 115 contained yeastlike fungi and other organisms, were tested in blind trials by use of a monoclonal antibody. Sensitivity was 100% with 3- to 4+ fluorescence on all cryptosporidial oocysts, both in light and heavy infections. The organisms were round and easily visible (4 to 6 micron), showing apple-green to yellow fluorescence against a dark background free of nonspecific fluorescence. Specificity was also 100% with all 99 positive Cryptosporidium sp. specimens exhibiting fluorescence and all 198 negative specimens showing no fluorescence. All positive and negative specimens were previously confirmed by the hot modified acid-fast technique. However, seven specimens previously considered negative by this acid-fast method were positive by the monoclonal antibody technique. These specimens were confirmed as positive, after extensive examination of additional smears prepared by the modified hot acid-fast method revealed rare organisms, emphasizing the increased sensitivity of the monoclonal antibody technique. Since acid-fast stains do not always consistently stain all oocysts, the increased sensitivity of the monoclonal reagent provides an excellent screening method.

Antibodies, Monoclonal↗

PubMed1986

Blood parasites: problems in diagnosis using automated differential instrumentation.

To examine potential problems inherent in using automated differential instruments, we have reviewed herein two cases where blood parasites, Plasmodium vivax and Plasmodium falciparum, were completely missed by use of this method. Diagnosis of these infections was made when blood was sent to the parasitology laboratory after having been missed prior to that time. The first problem involved the laboratory request slip; no indication was made concerning possible suspect organisms. Therefore, peripheral blood examinations were performed using automated equipment. The number of fields scanned by a technologist on these smears is quite low; thus failure to pick up a light parasitemia is almost guaranteed. In both cases, after diagnosis had been made on smears submitted to the parasitology division, all previous smears examined by the automated system were reviewed and found to be positive for parasites. Failure to make the diagnosis resulted in delayed therapy. Although these instruments are not designed to detect intracellular blood parasites, the inability of the automated systems to discriminate between uninfected red blood cells and those infected with parasites may pose serious diagnostic problems.

Adult↗

PubMed1986

Sinus tract extension of a liver hydatid cyst and recovery of diagnostic hooklets in sputum.

A 67-year-old man, born in Turkey but living within the United States since 1975, presented with a four-month history of right lower chest pain. Chest x-ray revealed a right lower lobe infiltrate. Liver scan revealed multiple calcified cysts consistent with unilocular hydatid disease. The patient was taken to surgery for liver cysts removal. Although there was no specific evidence of lung cysts, it was recommended that sputum specimens be submitted for evidence of hydatid sand, i.e., hooklets and scolices. Hooklets were found, thus confirming the sinus tract connection between lung and liver. This case emphasizes the point that hooklets can be recovered in sputum and identified, even when there are few present. This approach also represents a noninvasive procedure that, along with serology, could be used as an alternative to biopsy technics under certain conditions.

Aged↗

PubMed1985

Special laboratory examinations for parasitic infections.

Besides the routine procedures used for the diagnosis of parasites, there are a number of other diagnostic techniques available for the recovery and identification of parasites. Most laboratories do not routinely offer all of these techniques, but many are relatively simple and inexpensive to perform. This article discusses these techniques and their clinical relevance.

Animals↗

PubMed1985

Babesiosis: problems in diagnosis using autoanalyzers.

A 76-year-old white man previous diagnosed as having Waldenstrom's macroglobulinemia continued with persistent fevers and sweats for two and a half years. Recently, repeated automated differentials during 11 days of hospitalization failed to note any intracellular inclusions in the RBCs. Blood sent to the Microbiology Laboratory was noted to contain Babesia species. A review of the hematology slides revealed that Babesia species was present on all the slides the analyzer had screened. This failure to note infected RBCs may pose serious diagnostic problems.

Aged↗

PubMed1983

Dientamoeba fragilis, a protozoan parasite in adult members of a semicommunal group.

Dientamoeba fragilis is an intestinal protozoan parasite associated with gastrointestinal symptoms. This study was undertaken in a semicommunal group reported to have a high prevalence of this parasite. Stools were collected from 81 adult group members. Intestinal parasites were observed in stool specimens of 45 (56%) of the 81 adults; D. fragilis was found in 33 (41%) subjects. This paper describes the clinical findings and treatment of 26 adults with D. fragilis alone or with a commensal. Gastrointestinal symptoms were observed in 22 (85%) of infected subjects; abdominal pain and excessive flatus were significantly more common in this group. diiohydroxyquin 650 mg three times a day for 20 days eliminated the parasite in 10 (83%) of the 12 treated, although three subjects required a second course of therapy. Parasitic infection should be considered in patients with vague gastrointestinal symptoms, especially those living in endemic areas, in close proximity, or with a history of foreign travel.

Adolescent↗

PubMed1983

Evaluation of intestinal parasite morphology in polyvinyl alcohol preservative: comparison of copper sulfate and mercuric chloride bases for use in Schaudinn fixative.

As a result of disposal problems inherent in the use of mercury compounds, many laboratories have considered using copper sulfate as a substitute for mercuric chloride in polyvinyl alcohol (PVA) preservative. The primary use for PVA-preserved specimens is the permanent stained smear, the most important technique for the identification of intestinal protozoa. A comparison of organism recovery and morphology was undertaken with PVA containing either copper sulfate or mercuric chloride base. Paired fecal specimens (417 pairs) were collected and examined with the Formalin-ether concentration and Trichrome stain techniques. Numbers of organisms recovered and helminth egg and protozoan morphology were assessed from the concentration sediment. Morphology, clarity of nuclear and cytoplasmic detail, overall color differences, and the ease or difficulty in detecting organisms in fecal debris were assessed from the permanent stained smear. No significant differences were found in the numbers and morphology of organisms seen in the concentration sediment. However, when the trichrome stain was used, the overall morphology of the intestinal protozoa preserved in PVA with copper sulfate was not equal to that seen with PVA with mercuric chloride. We do not recommend switching from mercuric chloride base to copper sulfate base unless that is the only option available for the preparation of permanent stained smears.

Copper↗

PubMed1983

Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens.

Due to increasing numbers of patients with documented infections with Cryptosporidium and other coccidia, it is important for the physician and clinical laboratory to be aware of the appropriate diagnostic techniques necessary for organism recovery and identification. Although Cryptosporidium is found in the gastrointestinal tract, tissue biopsies may be insufficient for organism recovery; the examination of stool specimens is a noninvasive procedure and will provide better overall opportunities for organism recovery. Human clinical specimens were examined from 45 patients with confirmed cryptosporidiosis or suspected of having the infection. Tissue biopsy sections, fecal wet preparations, and permanent stained smears were examined. Stool specimens were submitted in 10% Formalin, 2.5% potassium dichromate, and polyvinyl alcohol and were examined for oocysts by using 15 different methods: phase-contrast and light microscopy; Sheather's sugar flotation; Formalin concentration techniques; 10% potassium hydroxide; Giemsa; trichrome; periodic acid-Schiff; modified periodic acid-Schiff; silver methenamine; acridine orange; auramine-rhodamine; Kinyoun acid-fast; Ziehl-Neelsen carbolfuchsin; and a modified acid-fast procedure. Each technique or combination of techniques was assessed by organism quantitation, organism morphology, and ease of visual recognition. Based on these comparative studies, the modified Ziehl-Neelsen carbolfuchsin stain on 10% Formalin-preserved stool is recommended for the recovery and identification of Cryptosporidium.

Acquired Immunodeficiency Syndrome↗

PubMed1983

Intestinal protozoan infection in a semicommunal group.

A survey was conducted to determine the prevalence of protozoan parasites in a large semicommunal group in Los Angeles. Protozoan parasites were observed in 151 (69%) of the 220 group members in the study. Parasites were observed in stool specimens from 105 (76%) of the 138 children and 46 (56%) of the 82 adults. Dientamoeba fragilis was observed in 115 (52%), Giardia lamblia in 50 (23%), Entamoeba histolytica in 9 (4%), and commensals in 61 (28%). Parasitic infection was infrequent in infants less than 1 year old, was demonstrated in 33 (89%) of the 2- to 4-year-olds, 69 (78%) of the 89 school age children 8-15 years of age, and in 46 (56%) of the 82 adults. G. lamblia was most prevalent in children younger than 6 years; whereas D. fragilis was common in all age groups. The fecal-oral route was the most likely means for parasite transmission. Since the group at times serves meals to the public, spread of parasites outside the community is a potential public health problems. Diagnosis of parasitic infection is dependent on optimal stool collection, proper laboratory techniques and trained personnel.

Adolescent↗

PubMed1982

Comparison of indirect fluorescent-antibody amoebic serology with counterimmunoelectrophoresis and indirect hemagglutination amoebic serologies.

Patients ranged from those with no prior diagnosis of or suspected exposure to Entamoeba histolytica to those with proven amoebic liver abscesses (extraintestinal disease). A comparison of serologies from patients with proven and suspected amoebiasis or possible past exposure revealed good correlation between the indirect fluorescent antibody (IFA) procedure and the other methods used, counterimmunoelectrophoresis and indirect hemagglutination. Titers from patients with proven extraintestinal amoebiasis were in the expected high range previously reported by other authors. Patients with clinical histories suggestive of exposure to E. histolytica but no proven disease had lower titers which indicated possible background exposure. The IFA procedure provides a rapid method of antibody detection; results obtained on an emergency basis provide essential information in making the diagnosis of amoebic abscess, pyogenic abscess, or tumor. The IFA procedure is rapid, reliable reproducible, and relatively inexpensive to perform, provided a good source of antigen is consistently available.

Amebiasis↗