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L D Hendricks

Publications and source records attributed to L D Hendricks.

At least 19 recordsLinked to original sources
PubMed1993

Leishmania donovani parasites in the nasal secretions, tonsillopharyngeal mucosa, and urine centrifugates of visceral leishmaniasis patients in Kenya.

In the early 1930s, investigators of visceral leishmaniasis stated that Leishman-Donovan bodies are found in body fluids of kala-azar patients, for example, in urine, feces, semen, and nasal and pharyngeal secretions. Based on this finding, we investigated the diagnostic potential of nasal secretions, tonsillopharyngeal mucosal swabs, and urine centrifugates inoculated into Schneider's Drosophila Medium (containing antibiotics and antifungal agents) as well as with Giemsa-stained smears. Consequently, 64 randomly selected patients with visceral leishmaniasis from Kenya (59 who were splenic culture or Giemsa stain positive and five who were culture negative but Giemsa stain positive) were tested by three noninvasive methods. These tests were all performed before the patients were treated with Pentostam. Cultures of nasal and tonsillopharyngeal swabs and urine centrifugates produced 28 positive samples representing 24 patients (37.5%). Moreover, a set of 25 Giemsa-stained slide smears made from the nasal and tonsillopharyngeal mucosa of 25 patients with visceral leishmaniasis who had not tested positive in cultures produced nine positives. Therefore, the overall total of patients who tested positive by all of the above methods was 33 or 51.6%. The cryopreserved Leishmania isolates were characterized by cellulose acetate electrophoresis using 20 enzyme systems. The isoenzyme profiles produced by the parasites were represented in five different L. donovani s.l. zymodemes. Representatives of these isolates were also characterized by DNA Southern blotting analysis, which corroborated the isoenzyme results.

Adolescent↗
PubMed1992

Biochemical characterization and zymodeme classification of Leishmania isolates from patients, vectors, and reservoir hosts in Kenya.

A total of 407 Leishmania and other Leishmania-like isolates obtained from patients, other vertebrates, sand fly vectors, and other arthropods from Kenya and other countries were characterized and compared with several World Health Organization and other well-characterized reference strains of Leishmania, Trypanosoma, Crithidia, Herpetomonas, and Leptomonas by cellulose acetate electrophoresis (CAE), using 20 enzyme systems. Analysis of the isoenzyme banding patterns (IBP) of the isolates generated isoenzyme profiles that were resolved as zymodemes and tabulated. Isolates that produced similar isoenzyme profiles in all 20 enzyme systems were placed into a particular Leishmania isoenzyme taxon, with the zymodeme designated numerically as Zn. A total of 66 zymodemes were recorded for the 407 isolates studied. To obviate the need to draw all 66 representative IBP for each of the 20 enzyme systems, the 66 zymodemes (Z1-Z66) were again placed into similarity groups represented by pattern number or Pn. This resulted in 23-50 IBP (Pn) per enzyme system. The highest number of IBP scored was for malate dehydrogenase (MDH) (P1-50) and the lowest score was for glucose-6-phosphate isomerase (GPI) (P1-23). From these different isoenzyme profiles or zymodemes, IBP of 14 (MDH, GPI, nucleoside hydrolase, phosphoglucomutase, malic enzyme, isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase, mannose-6-phosphate isomerase, 6-phosphogluconate dehydrogenase, glutamate oxaloacetate transferase/aspartate aminotransferase, glutathione reductase, superoxide dismutase, fumarase, and glyceraldehyde-3-phosphate dehydrogenase) of the 20 enzyme systems were selected for computer-calculated numerical taxonomy. Consistent individual isoenzyme bands with similar relative mobilities of the 14 enzyme systems were scored into groups (allelomorphs, allozymes, or electromorphs) and used in cluster analysis. For each pattern in every profile, the presence of a consistent band was entered as 1 and its absence as 0. A total of 419 allozyme characters (variables) were scored for the 14 enzyme systems. Lastly, all different zymodemes sharing a particular IBP (Pn) within an enzyme system were counted and the total number was shown as a zymodeme frequency (Zf). Final analysis of the CAE isoenzyme profiles and cluster-dendrograms resulted in the identification of several potentially new species and subspecies of Leishmania and other Leishmania-like isolates from patients, sand flies, and animal reservoir hosts collected from Kenya and other locations in Africa. Zymodeme analysis of the Kenyan visceral and cutaneous leishmaniasis isolates resulted in the identification of 11 subpopulations of the L. donovani species complex and six subpopulations of the L. tropica species complex endemic to different geographic areas of Kenya.

Animals↗
PubMed1991

Concurrent infection with Leishmania donovani and Leishmania major in a Kenyan patient: clinical description and parasite characterization.

Leishmania isolates aspirated a few months apart from the spleen of an indigenous adult male kala-azar patient from Baringo District, Kenya, were biochemically characterized and compared. The patient lived within a dual focus of L. donovani kalazar and L. major cutaneous leishmaniasis. A primary Leishmania isolate from splenic aspirates was cryopreserved (NLB-294). The patient was treated with sodium stibogluconate for kala-azar and discharged. Three months later, he had clinical relapse and returned for retreatment. During his second visit, the patient participated in a diagnostic study in which urine and nasopharyngeal samples were cultured for leishmaniasis. Urine, nasopharyngeal, and splenic samples were positive for Leishmania. Secondary isolates from splenic (NLB-294-I) and urine (NLB-318) cultures were cryopreserved and characterized by cellulose acetate electrophoresis (CAE) using 20 enzymes. Whereas the urine isolate was typed as L. donovani, the splenic aspirate culture revealed a mixed infection with L. donovani and L. major. The primary isolate (NLB-294) was then characterized and also showed a mixed infection. To exclude the possibility of protein post-translational modifications in electrophoretic assays, the primary and secondary isolates were grown and processed under identical cultural and lysis conditions, and compared using CAE. The results were identical to the first electrophoretic assays showing mixed promastigote banding patterns. Stationary-phase promastigotes of the secondary splenic isolate (NLB-294-I) inoculated subcutaneously, intraperitoneally, and intracardially into Syrian hamsters and BALB/c mice produced both kala-azar and cutaneous leishmaniasis within 6.5 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Mouse foot-pad inoculation as an aid to the isolation of Leishmania spp. from patients.

Portions of splenic or subcutaneous saline aspirates from suspected visceral or cutaneous leishmaniasis patients were inoculated into NNN media with an overlay of Schneider's medium or Schneider's medium alone for routine parasitological diagnosis. The remaining portions of the aspirates were used for preparing Giemsa-stained smears and for subcutaneous inoculation into hind foot-pads of Balb/c mice. Saline aspirates obtained from the foot-pads 2-14 d after inoculation were inoculated into Schneider's medium and examined for promastigotes. Parasite isolation was achieved from 90% of confirmed leishmaniasis patients by either culture method alone. Mouse foot-pad aspiration demonstrated parasites in 95% of all patients, and in over 80% of the confirmed cases of leishmaniasis. Combined culturing and aspirate smear examination was more efficient than foot-pad inoculation alone for the demonstration of leishmanial infection. Foot-pad aspiration does not entail killing animals and was sensitive for parasite isolation; it may be a useful short-term adjunct to existing parasite isolation methods, especially under field conditions where the risks of culture contamination may be high.

Animals↗
PubMed1988

Indigenous human cutaneous leishmaniasis caused by Leishmania tropica in Kenya.

Six Leishmania isolates from 3 indigenous Kenyans (2 isolates from one patient) and 2 Canadian visitors in Kenya were characterized by cellulose acetate electrophoresis. The isolates were compared among themselves and with reference strains of Leishmania donovani, L. aethiopica, L. major, L. tropica, and L. arabica using 9 enzymes: malate dehydrogenase (MDH), malic enzyme (ME), phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), aspartate aminotransferase (ASAT), adenylate kinase (AK), mannose phosphate isomerase (MPI), glucose phosphate isomerase (GPI), and phosphoglucomutase (PGM). Enzyme migration patterns of isolates from the 3 indigenous Kenyans were indistinguishable from those of 2 L. tropica reference strains. The isolates from the 2 Canadians yielded migration patterns of 7 enzymes that were indistinguishable from those of 2 L. tropica reference strains. However, migration patterns of 2 enzymes, PGM and ME, differed from all migration patterns of the 10 reference strains. Balb/c mice were inoculated with stationary phase promastigotes cultured from 3 stabilates from the lesions of 2 of the Kenyan patients. The mice developed no gross pathological lesions in 6 months time. All of the study patients developed cutaneous leishmaniasis while living in or visiting districts in Central and Rift Valley Provinces, Kenya. This is the first report of human cutaneous leishmaniasis caused by L. tropica indigenous to Africa south of the Sahara.

Adolescent↗
PubMed1987

Leishmania major: the suitability of East African nonhuman primates as animal models for cutaneous leishmaniasis.

The susceptibility of four species of East African nonhuman primates to experimental infection with Leishmania major was investigated. Four Syke's monkeys (Cercopithecus mitis), two vervet monkeys (Cercopithecus aethiops), two baboons (Papio cynocephalus), and two brown bushbabies (Galago garnettii) were each inoculated intradermally on the left eyelid, left ear, and nose with 0.1 ml of medium containing 1 x 10(7) promastigotes of a characterized L. major strain. All the nonhuman primates except the bushbabies developed erythema and conspicuous nodules on the eyelids and ears by 3 weeks PI. The nodules increased rapidly in size and ulceration was evident on the eyelids and ears by 49 days PI in the vervets, Syke's, and baboons. The aspirates were positive in culture or smears at 35, 49, 63, and 77 days PI. No parasites were observed in cultures or smears at 92, 105, 128, 147, and 161 days PI. The lesions in these animals began resolving by 84 days PI and were completely healed by 112 days PI. The exception was one baboon in which lesion healing did not start until around 147 days and was completely healed by 182 days PI. Cultures from the liver failed to demonstrate visceralization of the parasite in any of the animals throughout the 68 weeks of the experiment. Challenge with the same strain of L. major 6 months PI, corresponding to about 3 months after self cure, failed to produce infection in any of these experimental hosts. All the nonhuman primates except the bushbaby when challenged with the same strain of L. major at 12 months PI developed lesions and were positive for parasites at 14 and 28 days PI. Positive cultures were obtained from the eyelid and ear of one vervet up to 42 days PI. However, the lesion sizes in all these animals were smaller than in the initial infection and did not ulcerate. The nodules disappeared within 6 to 8 weeks as compared to 16 weeks in the initial infection. The histopathological appearance of the lesions varied from diffuse infiltration of plasma cells and lymphocytes which increased progressively to granulomata with epitheloid cells. This study shows that the vervets, Syke's, and the baboons are equally susceptible to L. major infection, while bushbabies are refractory. The vervets, Syke's, and baboons demonstrate a self-healing phenomenon within about 3 months which is comparable to that observed in humans infected with L. major. These three species of nonhuman primates are therefore considered as suitable models for drug or vaccine trials against human zoonotic cutaneous leishmaniasis.

Animals↗
PubMed1987

Cutaneous leishmaniasis caused by Leishmania tropica in Kenya.

9 leishmanial strains, isolated from cutaneous papulonodular lesions on 3 patients, were characterized by cellulose acetate electrophoresis using 7 enzymes. The patterns obtained were indistinguishable from those of a Leishmania tropica reference strain and these 9 strains were similar to L. tropica in failing to infect mice. Although these 3 patients were Americans, their only potential exposure to sandflies was in Kenya, and thus they are believed to be the first cases of cutaneous leishmaniasis due to L. tropica in Kenya.

Animals↗
PubMed1987

Comparative infectivity of a Kenyan strain of Leishmania donovani amastigotes for Rattus rattus and the laboratory white rat.

Amastigotes of a Kenyan strain of Leishmania donovani from a previously infected hamster were used to inoculate Rattus rattus and the laboratory white rat intracardially. The animals were sampled at 2, 4, 6, and 12 weeks post-inoculation to determine infectivity and total parasite burdens in the liver and spleen. Higher parasite burdens were observed in the livers and spleens of R. rattus. Parasite culture indicated more generalized parasite dissemination compared to the white rat. Demonstration of the parasite in dermal tissue of R. rattus at 2 and 4 weeks suggests that the parasite may be accessible to sandfly vectors. Transient susceptibility to systemic infection and parasite survival in dermal tissue suggests a potential role of R. rattus in the transmission cycle of Kenyan visceral leishmaniasis.

Animals↗
PubMed1987

Isozyme variation in Simulium (Edwardsellum) damnosum s.l. (Diptera: Simuliidae) from Kenya.

Isozyme variation of the Simulium damnosum sibling species complex was studied by cellulose acetate electrophoresis (CAE) from four Kenyan river systems. Two enzymes, PGM and HK, were diagnostic and differentiated the larvae collected in Western and Nyanza provinces from the larvae collected at Mt. Kenya. Allele frequency differences of the enzyme PGI allowed about 75% separation of the geographically distinct populations.

Alleles↗
PubMed1986

Characterization of Simulium (Edwardsellum) damnosum s.l. populations from six river systems in Kenya by cellulose acetate electrophoresis.

Isoenzyme characterization of the Simulium damnosum Theobald sibling species complex from two widely separated geographical areas in Kenya is presented based on 10 enzymatic loci. Four river systems in Western and Nyanza Provinces, namely, the Yala, Lusumu, Isiukhu and the Nzoia harbouring S. damnosum s.l. were compared among themselves and with S. damnosum s.l. collected from the Thiba and the Nyamindi river systems in the Mt. Kenya area. The two populations were easily separable using PGM, HK and, more than 73% of the time, with PGI. Using the first two enzymatic loci, PGM and HK, all the western Kenya S. damnosum s.l. belong to the same population while those from Mt. Kenya areas belong to a different population. In both geographical zones there was less than 20% qualitative and quantitative polymorphism within infraspecific forms in any given breeding area of S. damnosum s.l. Three enzymes, ME, XDH, and G-6-PDH had isomorphic mobilities for both the Mt. Kenya and western Kenya populations. Four other enzyme/substrate systems tested had no satisfactory resolution as a diagnostic value.

Animals↗
PubMed1986

Characterization of Kenyan Leishmania spp. and identification of Mastomys natalensis, Taterillus emini and Aethomys kaiseri as new hosts of Leishmania major.

A survey to examine rodents for leishmanias was initiated in the Perkerra Settlement Scheme, Marigat, Baringo District, Kenya, 789 rodents of ten different species were trapped and examined. Leishmanial parasites were isolated from the spleen and liver of 17 animals of five different species: seven from Tatera robusta, five from Arvicanthis niloticus, two from Mastomys natalensis, two from Taterillus emini and one from Aethomys kaiseri. These were identified as L. major by enzyme electrophoresis, using 12 enzymes, and by excreted factor (EF) serotyping. The isolation of L. major from Mastomys natalensis, Taterillus emini and Aethomys kaiseri represent newly recorded hosts of L. major.

Animals↗
PubMed1985

American cutaneous leishmaniasis: a comparison of three sodium stibogluconate treatment schedules.

Thirty-six patients with American cutaneous leishmaniasis were randomized to receive intravenous sodium stibogluconate for 10 days at a dose of 600 mg antimony (Sb) per day by one of three schedules: once daily by rapid infusion (A), by continuous 24 hr infusion (B), or in divided doses every eight hours by rapid infusion (C). Patients not cured after initial treatment were rerandomized to one of the other treatment schedules. An additional 19 patients who were not part of the randomized study received standard (STD) sodium stibogluconate treatment (600 mg Sb once daily by rapid infusion for 10 days, identical with schedule A). In the randomized study, the overall cure rate after the first course of treatment was 64%, but was higher for schedule A (100%) than for B (50%) or C (42%) (P less than 0.01). Considering all courses of treatment, schedule A was more effective (94%) than B (53%) or C (43%) (P less than 0.01). Paradoxically, patients in group A had a higher cure rate than patients in group STD (42% after the first course of treatment and 51% when all courses of treatment were considered). Side effects were mild and well tolerated. Total side effects were more frequent in groups B + C (52%) than A + STD (23%) due to an increased incidence of subjective complaints (26% vs. 10%, P less than 0.05) in patients receiving other than once daily rapid infusion. We conclude that giving the same total amount of sodium stibogluconate in three divided doses or by continuous infusion offers no advantage over standard, once daily treatment of American cutaneous leishmaniasis.

Antimony Sodium Gluconate↗
PubMed1984

Leishmania mexicana: purine metabolism in promastigotes, axenic amastigotes, and amastigotes derived from Vero cells.

Leishmania mexicana mexicana promastigotes, axenic amastigotes, and amastigotes derived from Vero cells were examined for de novo purine synthesis and mechanisms of purine salvage. Both promastigotes and axenic amastigotes were incapable of de novo purine synthesis, as shown by the lack of [14C]formate and [14C]glycine incorporation into purine nucleotide pools. However, the ready incorporation of [14C]hypoxanthine, [14C]adenine, and [14C]guanine suggested that purine salvage pathways were operating. In addition, a significant percentage (greater than or equal to 60%) of the total label from these purine precursors was associated with adenylate nucleotides. Nucleotide pool levels of axenic amastigotes were consistently greater but the specific activities were less than those of promastigotes, suggesting a slower rate of purine metabolism in the axenic amastigote form. Similar results were obtained from amastigotes isolated from infected Vero cells.

Adenine↗
PubMed1984

Inbred mice as model hosts for cutaneous leishmaniasis. I. Resistance and susceptibility to infection with Leishmania braziliensis, L. mexicana, and L. aethiopica.

The susceptibility of 12 strains of inbred mice representing a broad genetic spectrum to infection of Leishmania braziliensis, L. mexicana and L. aethiopica was determined. Levels of susceptibility were evaluated by gross morphology of lesions, evidence of resolution, persistence of parasites at the site of inoculation, and visceralization to the spleen or liver following inoculation in noses. Very different patterns of responses were noted among the infections with the three species of Leishmania. Among the strains of inbred mice infected with L. braziliensis, patterns of cutaneous lesion development indicated a broad range of susceptibilities and responses. Two strains of inbred mice (AKR/J and CBA/J) showed only a slight and transient swelling of the nose. The SWR/J, C57L/J, A/J, A/HeJ and DBA/1J showed initial swellings or nodules which eventually resolved. In contrast, the BALB/cJ mice were ranked as most susceptible, based on progressive dermal lesions and visceralization. Four strains of inbred mice (C3H/HeJ, C57BL/6J, CBA/J and CBA/CaJ) showed no evidence of infection. Lesion development in most strains of inbred mice infected with L. mexicana occurred later than with L. braziliensis but was then more rapidly progressive with no indication of resolution. Two strains (C3H/HeJ and C57BL/6J) showed no evidence of infection. Only slight swellings of the nose were seen in the 12 strains of inbred mice infected with L. aethiopica; however, parasites were isolated by culture from apparently normal noses in five groups (A/HeJ, AKR/J, BALB/cJ, DBA/2J and SWR/J).

Animals↗
PubMed1984

Liposomes in leishmaniasis: effects of parasite virulence on treatment of experimental leishmaniasis in hamsters.

During studies on the use of liposomes as drug carriers in experimental leishmaniasis in hamsters, we noted incidentally that the apparent virulence of the infection often varied widely between different large groups of animals. When the death rates among control animals (injected only with saline) were compared with hepatic parasite counts of survivors in the same group, three distinctive types of infection were observed: type I, low death rate, low parasite count in survivors; type II, high death rate, low parasite count in survivors; type III, high death rate, high parasite count in survivors. The apparent virulence, based on death rates both at early and late stages of infection, was in the order I less than II less than III. Therapeutic efficacy of a drug (meglumine antimoniate) or liposome-encapsulated drug against each type of infection was in the order I greater than II greater than III. Liposomes reduced the drug dose required for each infection type many hundred-fold and reduced the death rate for type I to zero. However, among animals with type III (or even type II) infection certain individuals were completely refractory to treatment, even when liposome-encapsulated drug was employed, and the lowest mortality rate achieved was approximately 30%. This latter resistance to treatment may have been due to irreversible tissue damage caused by advanced disease, or it may have reflected resistance of certain virulent infections to treatment.

Animals↗
PubMed1984

Visceral leishmaniasis in the German shepherd dog. I. Infection, clinical disease, and clinical pathology.

Two groups of three German shepherd dogs each were inoculated with Leishmania chagasi or Leishmania donovani amastigotes and the infection was followed for 82 days. The dogs developed a persistent infection, became thin, and developed splenomegaly and lymphadenomegaly by 55 days after inoculation. All dogs developed a normocytic, normochromic anemia of increasing severity. Thrombocytopenia and leukopenia occasionally occurred. Blood tryptophan levels were decreased significantly in infected dogs. Increased total serum protein, with hypergammaglobulinemia and hypoalbuminemia, was present in all dogs to various degrees. There was a marked increase in gamma globulins, with smaller increases in alpha and beta globulins. Many of the clinicopathologic changes observed in these dogs were similar to the disease as it occurs in man. The German shepherd dog may be a useful laboratory model for the study of visceral leishmaniasis.

Anemia↗