Intermediate-term outcomes of 350-mm(2) Baerveldt glaucoma implants

OBJECTIVE

To determine the intermediate-term outcome of 350-mm(2) Baerveldt glaucoma implants.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Sixty-five patients (65 eyes).

INTERVENTION

Implantation of 350-mm(2) Baerveldt glaucoma drainage device.

MAIN OUTCOME MEASURES

Intraocular pressure, number of glaucoma medications, best-corrected Snellen visual acuity, length of follow-up, risk factors for failure, and complications.

RESULTS

Mean intraocular pressure was reduced from a preoperative value of 32 mmHg to a 2-year postoperative value of 14 mmHg (56% reduction, P < 0.001). Success rates at 2-year follow-up were 71%, 81%, 78%, 60%, and 47% for the overall group, primary open-angle glaucoma group, neovascular group, uveitic group, and other group, respectively. After accounting for the effect of diagnosis group, significant risk factors in the overall group for failure at 2 years included younger age, high preoperative intraocular pressure, and more prior incisional surgeries. Glaucoma medication use in our overall study population was reduced from 2.5 mean preoperative medications to 0.8 postoperative medications (68%). Median change in Snellen visual acuity between preoperative and 2-year postoperative visits was not significant in the overall group. Postoperative complications included choroidal effusion in 15 patients (23%), tube obstruction by blood or vitreous in five patients (8%), phthisis in four patients (6%), aqueous misdirection in two patients (3%), strabismus in two patients (3%), tube-cornea touch in two patients (3%), endophthalmitis in two patients (3%), and retinal detachment in two patients (3%). No patients had suprachoroidal hemorrhage.

CONCLUSIONS

The 350-mm(2) Baerveldt glaucoma implants are a safe and effective treatment for intermediate-term intraocular pressure control in patients with refractory glaucoma.

Baerveldt drainage implants in eyes with a preexisting scleral buckle

OBJECTIVE

To describe the surgical insertion of a Baerveldt drainage implant and postoperative visual acuity and intraocular pressure (IOP) outcomes in patients with a preexisting scleral buckle.

METHODS

Medical records of all patients with a preexisting scleral buckle who underwent insertion of a Baerveldt drainage implant at Bascom Palmer Eye Institute, Miami, Fla, from January 1, 1994, through December 31, 1998, were reviewed. Outcome measures included visual acuity and IOP at 1 year.

RESULTS

At 1 year postoperatively, 14 (88%) of 16 patients had stable or improved visual acuity. Preoperatively, mean IOP was 30.9 mm Hg and the mean number of antiglaucoma medications was 3.4; at 1 year postoperatively, mean IOP was 12.0 mm Hg and the mean number of antiglaucoma medications was 0.8 (P<.001). Nine patients (56%) achieved an IOP of greater than 5 and no greater than 21 mm Hg without medication, and an additional 7 (44%) achieved this level of IOP control with medication. No patient required further surgery for uncontrolled IOP during the follow-up interval, which ranged from 19. 1 to 45.5 months.

CONCLUSION

Baerveldt drainage device insertion behind or over a preexisting encircling band is often successful in managing refractory glaucoma in patients who have undergone previous scleral buckling procedures. Arch Ophthalmol. 2000;118:1509-1513

Transpupillary thermotherapy for small choroidal melanoma

PURPOSE

To report the treatment of small choroidal melanoma with transpupillary thermotherapy.

METHODS

We examined a nonrandomized and uncontrolled series of 14 eyes of 14 patients who were followed up with serial ophthalmoscopy, ultrasonography, and photography. Transpupillary thermotherapy was performed upon documented evidence of tumor growth.

RESULTS

After transpupillary thermotherapy, mean follow-up +/- SD was 16 +/- 6.41 months (range, 7 to 28 months) with 10 eyes followed up for at least 1 year. The mean preoperative tumor height was 1.79 +/- 0.59 mm (range, 0.78 to 2.60 mm). Six months after treatment, the mean height was 0.54 mm +/- 0.57 mm (range, 0.00 to 1.16 mm). In 10 eyes, the treated lesion flattened entirely with a mean interval between treatment and flattening of 8.7 months (range, 3 to 21 months). Three patients required retreatment for lack of regression or recurrent growth. The average time to retreatment was 11 months (range, 5 to 15 months). No eye was retreated more than once. There were three amelanotic lesions, all treated in a single session without recurrence. Complications consisted of retinal hemorrhage, retinal vascular occlusion, retinal traction, exudative serous neurosensory detachment, vitreitis, and postoperative pain. The sole treatment failure occurred in an eye treated with a juxtapapillary tumor, with recurrence developing from a previously flattened lesion. This eye was enucleated 10 months after the single initial treatment. At the time of writing, there had been no tumor-related death.

CONCLUSIONS

Transpupillary thermotherapy may represent a viable treatment alternative for both pigmented and amelanotic small choroidal melanoma. Diligent follow-up is axiomatic because retreatment may be necessary. Recurrent tumors may develop from flat lesions. Juxtapapillary tumors may be at higher risk for recurrence. Definitive statements regarding the role of transpupillary thermotherapy in the management of small choroidal melanoma await 5-year and 10-year morbidity and mortality data.

Epibulbar allergic granulomatous nodules in a human immunodeficiency virus-positive patient

PURPOSE

To report an unusual epibulbar inflammatory process in a patient with human immunodeficiency virus (HIV).

METHODS

Case report. A 32-year-old man developed fleshy epibulbar nodules on his right conjunctiva and cornea after being treated for conjunctivitis. A biopsy of the lesions was done, and the specimen was processed for histopathologic examination.

RESULTS

The biopsy specimen contained inflammatory cells, including an eosinophilic abscess. The diagnosis was allergic granulomatous nodules.

CONCLUSION

This case illustrates the occurrence of epibulbar allergic granulomatous nodules in an HIV-positive patient.

Isolation of Trypanosoma brucei gambiense from northern Uganda: evaluation of the kit for in vitro isolation (KIVI) in an epidemic focus

867 individuals from 3 sites near the town of Adjumani in the East Moyo region of north-west Uganda were investigated clinically and serologically for evidence of current trypanosome infections. Blood samples were taken from 94 persons with a positive card agglutination test for trypanosomiasis (CATT) and clinical suspects and inoculated into the kit for in vitro isolation of Trypanosoma brucei gambiense (KIVI). Amongst this group, 30 parasitaemic individuals were identified by microhaematocrit centrifugation and the quantitative buffy coat technique (QBC). Only 80% of these isolates, and one isolate from an aparasitaemic individual, grew in culture. The success or failure of cultures from parasitaemic patients was unrelated to the size of the trypanosome inoculum. The implications of these results and possible reasons for the failure of KIVI are discussed.

A comparison of parasitological methods for the diagnosis of gambian trypanosomiasis in an area of low endemicity in Côte d'Ivoire

The card agglutination test for trypanosomiasis (CATT) was used to examine 8974 inhabitants in 14 village areas south-west of Daloa, Côte d'Ivoire; 114 (1.3%) were CATTT or +/-, and were further examined by one or more of 6 methods for the direct detection of trypanosomes: lymphatic gland puncture, stained thick blood film (TBF), haematocrit centrifugation technique (HCT), mini-anion exchange column (MAEC), quantitative buffy coat method (QBC), and kit for in vitro isolation of trypanosomes (KIVI). Trypanosomes were seen by at least one method in 16 (14.0%) of the CATT+ group. Blood from 356 of the 8860 CATT- group was inoculated into KIVI; trypanosomes grew from the blood of 1 person. Eleven of the 17 patients with detectable trypanosomes were screened by all 6 methods: 6 were HCT+; 7 were gland+; 10 were MAEC+; 10 were KIVI+; 11 were both TBF+ and QBC+. One CATT+ patient was KIVI+ but otherwise negative, although TBF was not done. The overall prevalence of trypanosomes was 0.2% rising to 0.8% in one village area. The results support previous evidence that a reappraisal of procedures is required in the customary system of surveillance for gambian sleeping sickness.

The persistence of genetic homogeneity among Trypanosoma brucei rhodesiense isolates from patients in north-west Tanzania

Trypanosomes isolated during 1991 from nine patients with Rhodesian sleeping sickness in north-west Tanzania were genetically characterized by electrophoresis of ten enzymes. Eight isolates were allocated to a known zymodeme (Z306); another had an enzyme profile (Z379) not previously encountered. An example of Z306 has been previously isolated in 1971, nearby in a part of Rwanda adjacent to the border with Tanzania; in addition, a closely related isolate, in Z307, was collected in 1959 from a patient in north-west Tanzania. The new zymodeme (Z379) was 94% similar to Z306, and both had a close similarity of 89% to Z307. All these isolates belonged to the zambezi strain group of related zymodemes, and evidence is presented that other examples of the group have been collected from man in Tanzania since 1959. Such apparent long term genetic stability is similar to circumstances further south in an endemic area of Zambia, where 12 examples of Z306 and two of Z307 were acquired over a period of 12 years from patients. The similar genetic homogeneity among trypanosomes in endemic parts of both Tanzania and Zambia contrasted markedly with the heterogeneity described to the north of Tanzania in that different strain groups circulate in epidemic areas of Kenya and Uganda.

Direct isolation in vitro of Trypanosoma brucei from man and other animals, and its potential value for the diagnosis of gambian trypanosomiasis

A recently described simple kit for isolating African trypanosomes in vitro (KIVI) was tested further with blood samples from man and other animals in Côte d'Ivoire and République du Congo. A high rate of success was achieved, with positive cultures being found 5-36 d after inoculation. The method was also of value in diagnosis. Parasitaemia was initially detected by the haematocrit method; in addition, the mini-anion exchange column was used for human blood and lymph fluid from patients with swollen glands was examined. The card agglutination test (CATT) was applied to the human blood samples. In Côte d'Ivoire, all 5 parasitaemic patients, who were also positive by CATT, yielded positive KIVI cultures. Of 15 animals, 2 parasitaemic and 10 apparently aparasitaemic individuals gave positive cultures. In the Congo, none of the 22 animals was parasitaemic and none gave a positive culture. Of 647 human subjects initially screened, 61, mostly with a positive CATT, were examined by KIVI; 20 gave positive cultures. Seven of these cultures originated from patients in whom no trypanosome had been seen in blood or lymph fluid, although blood from 2 parasitaemic patients failed to yield positive KIVI cultures. Some patients with CATT-negative whole blood and/or serum were positive by KIVI.

Numerical taxonomy of Trypanozoon based on polymorphisms in a reduced range of enzymes

Numerical analyses of Trypanozoon taxonomy are presented, based on the isoenzyme data of Stevens et al. (1992). The previous study used a reduced range of enzymes compared with earlier work; the analyses indicate the value of this rationalized system. Both recently isolated trypanosome stocks and previously studied populations were included, allowing detailed comparison with earlier studies. Relationships between zymodemes were calculated with an improved similarity coefficient program, using Jaccard's coefficient (1908), and by Nei's method (1972). Dendrograms were constructed from the matrices produced with the group-average method. The groupings produced by both numerical methods were in close agreement, and the clusters of related principal zymodemes largely matched the species, subspecies and strain groups proposed by previous workers. Trypanozoon biochemical taxonomy is reviewed and the groupings reinforced by this study are: the mainly East African strain groups, busoga, zambezi, kakumbi, kiboko and sindo; T.b. gambiense and the bouaflé strain group from West Africa, and T. evansi; an intermediate bouaflé/busoga group was also recognized.

Elusive trypanosomes

Professor Kershaw's encouragement of the development of anion-exchange separation of African trypanosomes from blood led to two decades of activity when, for the first time, considerable progress was made in the intrinsic characterization of these parasites. Such characterization depended on establishing high infections in laboratory rodents. However, the collection of samples from the field was restricted by the failure of certain trypanosomes either to infect, or to multiply adequately in, rodents. More recently, in vitro culture has come to play an increasingly important role in producing material. By obtaining procyclic forms directly from wild tsetse flies, or by transforming low numbers of bloodstream forms in field samples to the procyclic phase in experimental tsetse, trypanosomes of poor or nil infectivity to rodents were readily cultured in the large amounts required for biochemical characterization. A number of specimens of a new kind of Nannomonas, of Trypanosoma simiae, of T. grayi, and of an antigenically distinct T. brucei gambiense were found. Evidence is presented that many other kinds of trypanosome may be eluding isolation by their inability to infect rodents.

Trypanosoma congolense: the distribution of enzymic variants in east and west Africa

A total of 114 stocks of Trypanosoma congolense originating from Kenya, Uganda, Tanzania, Zambia and Sudan, but including, for comparison, stocks from The Gambia, Liberia, Ivory Coast, Nigeria and Cameroun, were compared by isoenzyme electrophoresis for 6 enzymes. The zymodemes were grouped, both from a dendrogram and using a cladistic method, after calculating the dissimilarity, or distance, between profiles. Previous observations are broadly confirmed, the zymodemes clustering separately according to geographical origin and ecological zone. Thus, one group was composed almost entirely of East African stocks, and another of stocks from both East and West Africa, although each group was of savanna origin. A third group was composed of stocks from the humid, rain-forest zones of West Africa, and was particularly characterized by isoenzyme variants of superoxide dismutase and glucose-phosphate isomerase. Two stocks from the Kenyan coast formed a markedly separate group, which may be taxonomically distinct.

Enzyme polymorphism and the identity of Trypanosoma brucei gambiense

Thirty-two isolates from man in known areas of Gambian trypanosomiasis, in the Sudan, Kenya, Zaire, Nigeria, Ivory Coast, Burkina Faso, Liberia and Senegal, were examined by isoenzyme electrophoresis of 11 enzymes. Comparisons were also made with our previously published results on 23 other stocks of similar origins, which had been examined in the same manner. All those stocks of low initial virulence to laboratory rodents, which thus conform to the accepted view of the behaviour of Trypanosoma brucei gambiense can be identified by characteristic combinations of enzyme patterns, especially certain aminotransferase markers. A limited study of superoxide dismutase polymorphism suggested a further marker of value. The isolates of high initial virulence to rodents, which are thus behaviourally akin to T. b. rhodesiense, did not share these characteristics. We conclude that there exists a homogeneous group of trypanosomes of wide dispersion throughout tropical Africa, characterized by certain isoenzyme combinations and low initial virulence to rodents, which corresponds to the classical concept of T. b. gambiense. The features of limited antigenic repertoire, high resistance to normal human serum and restriction fragment length polymorphisms of the genes for certain variant surface glycoproteins also appear to be characteristic of this group.

Isoenzyme changes during the life cycle of Trypanosoma cruzi

The isoenzyme profiles, for 14 enzymes, of amastigotes, trypomastigotes and epimastigotes were compared in various cloned and uncloned T. cruzi stocks belonging to different zymodemes. A culture method with a human diploid cell line was developed and produced either pure amastigotes or trypomastigotes in high yields. Trypomastigotes were also isolated from rat blood and from liquid culture. Epimastigotes were harvested from various acellular media and from the overlay of cell monolayers. The isoenzyme patterns of each life-cycle stage showed consistent differences in the number, position and intensity of the electrophoretic bands for certain enzymes. With the single exception of one peptidase, the variable patterns were stage-specific regardless of whether the organisms were harvested from animals or from various cultures at different temperatures.

Effects of dietary supplementation on autoimmunity in the MRL/lpr mouse: a preliminary investigation

The effects of dietary fatty acid supplementation on various disease parameters in the spontaneously autoimmune MRL-mp-lpr/lpr mouse model of systemic lupus erythematosus before onset of disease were investigated. A fat deficient diet was supplemented with the following oils: olive oil, sunflower oil, evening primrose oil (EPO), fish oil, and a fish oil/EPO mixture. The mice receiving a diet enriched with EPO showed an increase in survival, as did those receiving the fish oil/EPO mixture. These results, taken together with those of the other parameters monitored, suggest that EPO may be of benefit in alleviating the murine form of the disease.

[Presence of Leishmania major Yakimoff and Schokhor, 1914 in Mali. Enzymatic identification of a strain of human origin]

The first case of oriental sore reported to Leishmania major is identified in Mali. The characterization of the stain isolated from a left arm lesion of a 30 years old european woman is carried out by electrophoretic analysis using enzymes, i.e. PGM, PGI, G-6-PDH, 6-PGDH, IDH, MDH, ME, GOT.

Enzyme polymorphism and the distribution of Trypanosoma congolense isolates

Conditions were established for demonstrating, by electrophoresis, polymorphism in 12 soluble enzymes from Trypanosoma congolense. Three enzymes had identical mobilities in every stock, variation occurring among the remaining nine. Enzyme profiles were determined in 78 stocks collected from various hosts in a number of African countries, and were used by the computer to establish relationships within the collection. The major groupings formed solely from the isoenzymes corresponded remarkably closely to the origins of the stocks. Two distinct enzymic divisions formed, related only at the 20% level; Division A consisted entirely of stocks isolated in the humid coastal areas of West Africa, while Division B consisted mostly of stocks from drier zones throughout Africa. Some large groupings within these two main divisions also correlated with particular areas of origin within the major ecologic zones. The dry zone Division B included one group almost exclusively from East Africa, and two quite distinct enzymic groups from The Gambia; isolates from Liberia and Ivory Coast tended to fall into separate groups within the humid zone Division A. It is suggested that the differences between the major divisions may be associated with infraspecific adaptation to the different vector species occupying the separate habitats.

The sheep as a potential reservoir of human trypanosomiasis in the Republic of the Congo

The identical electrophoretic isoenzyme patterns of a human-plasma-resistant Trypanozoon stock from a sheep and of two other stocks from trypanosomiasis patients in the Congo Republic indicated that the sheep stock was probably infective to man. These, and one further human stock from the Congo, closely resembled stocks isolated from man in Liberia and Ivory Coast.

Epidemiological studies on the animal reservoir of Gambiense sleeping sickness. Part III. Characterization of trypanozoon stocks by isoenzymes and sensitivity to human serum

Polymorphism in 12 enzymes, as shown by electrophoresis on thin-layer starch-gel, was examined in 88 stocks of trypanosomes of the subgenus Trypanozoon isolated from man and animals in the Ivory Coast and Upper Volta. Three of the enzyme profiles seen in trypanosomes from man in the Ivory Coast were exactly the same as in trypanosomes from local domestic pigs and from various game animals and a bovine in the Upper volta, thus confirming previous evidence that human trypanosomiasis is a zoonosis in West Africa. Altogether 9 zymodemes were found in man; one was exactly the same as another from the Congo while a further one was identical to a Ugandan zymodeme. Thirty-one zymodemes were found only in animals, and 6 were exactly the same as others from elsewhere in Africa, including the eastern part. All zymodemes resembled each other by possessing common electrophoretic patterns in 5 enzymes. In most zymodemes, the variants of two other enzymes were characteristically West African, although an East African influence was apparent, together with further evidence of hybridization. Many zymodemes differed from others only to a minor extent in a few isoenzyme bands. A group of closely related minor zymodemes constituted another trypanosome population ineffective to man in West Africa which had a variable sensitivity to normal human serum; enzymatically it was clearly separated from the major zymodeme previously described in West Africa, which was consistently resistant to normal human serum and had been previously associated with chronic gambiense sleeping sickness.

Epidemiological aspects of three Trypanosoma cruzi zymodemes in Bahia State, Brazil

Culture forms of 104 stocks of Trypanosoma cruzi isolated in different regions of the State of Bahia were compared by electrophoresis of six enzymes. The three distinct combinations of isoenzyme patterns seen were designated ZI, Z2 and Z3. In an area of endemic Chagas's disease in eastern Bahia, T. cruzi Z1 was associated with sylvatic mammals and sylvatic triatomines, whereas T. cruzi Z2 was associated with a separate domestic cycleof transmission. T. cruzi Z1 was also found in sylvatic triatomines from other parts of the State. In contrast, in an area of the São Francisco Valley region of western Bahia, both T. cruzi Z1 and Z2 were isolated from man, domestic animals, and peridomestic rats. T. cruzi Z3 was isolated from an armadillo and from Panstrongylus geniculatus, a triatomine commonly found in armadillo burrows. Both T. cruzi Z1 and Z2 appeared to be pathogenic in man: T. cruzi Z1 was isolated from patients with acute Chagas's disease and from a single patient with chronic cardiac manifestations. T. cruzi Z2 was isolated from some asymptomatic individuals but was also associated with acute disease and chronic cardiac and digestive syndromes.

The identification of Trypanosoma brucei gambiense in Liberian pigs and dogs by isoenzymes and by resistance to human plasma

29 Trypanozoon stocks from Liberian pigs and dogs were screened for human plasma resistance and electrophoretic isoenzyme patterns of eleven enzymes. Two stocks from pigs were found both to be resistant to human plasma and to have an isoenzyme marker, a slow alanine aminotransferase (ALAT) pattern, previously found only in Trypanosoma brucei gambiense from man. This constitutes evidence that the pig is a reservoir of human trypanosomiasis in West Africa. The T.b.gambiense ALAT was also found in stocks from 5 other pigs and a dog, but none of these stocks was resistant to human plasma; conversely, 9 further isolations from pigs and 2 from dogs were plasma resistant but did not have the T.b.gambiense ALAT. The lack of correspondence between the two characteristics is discussed. A T.b.gambiense stock from man in Zaire had the ALAT pattern characteristic of T.b.gambiense from Senegal and Nigeria, together with the ASAT triplet found in most T.b.gambiense stocks. Peptidase polymorphism was shown in trypanosomes for the first time.

The influence of lorry transport on the Trypanosoma vivax infection rate in Nigerian trade cattle

In Nigeria in 1974 and 1975 there was an apparent sharp reduction in the prevalence of trypanosomiasis of cattle at several markets and control points. Some of the decrease appears to be due to the tsetse eradication programmes and Sahelian drought, but the change to lory transport as the principal means of moving cattle from the northern grazing areas to the south-western markets, which replaced a trek of at least three weeks, was probably an important factor.

Identification of economically important parasites

The taxonomy of a parasite can be an important guide to its pathogenic characteristics. A wide range of anatomical, biochemical and behavioural tests is now being developed to define different strains and subspecies of the main tropical parasites.

Biochemical characterization of some species of Trypansoma (Schizotrypanum) from bats (Microchiroptera)

Trypanosoma (Schizotryanum) species isolated from bats (Microchirotera) in Europe and Latin America were examined by determining the buoyant densities of their nuclear and kinetoplastic deoxyribonucleic acid (DNA) and the electrophoretic patterns of six isoenzymes. By these criteria they were separated into three distinct groups -- two from Europe (T. dionisii and T. vespertilionis) and one from America. T. dionisii was also separable by its morphology in vitro. Geographical location and DNA buoyant densities suggested that the American stocks were more closely related to T. cruzi than to the European species, though they differed from it marginally in kinetoplastic DNA density and in being noninfective to mice. Similar stocks studied by other workers have been shown to differ from T. cruzi also in reduced infectivity to, and lack of natural association with, Triatominae, and in antigenic composition. It is therefore proposed that trypanosomes of the subgenus Schizotryanum occuring naturally in Microchiroptera and differing from T. cruzi sensu stricto as outlined above should be treated as a distinct subspecies, T. cruzi marinkellei ssp. nov. T. cruzi sensu stricto thus becomes the nominate subspecies T. cruzi cruze Chagas 1909.

The identification by isoenzyme patterns of two distinct strain-groups of Trypanosoma cruzi, circulating independently in a rural area of Brazil

Culture forms of 17 Trypanosoma cruzi stocks, primarily isolated from a rural area of endemic Chagas disease at São Felipe, Bahia, Brazil, were compared by the electrophoretic patterns of six enzymes: aspartate aminotransferase, alanine aminotransferase, glucose-6-phosphate dehydrogenase, malate dehydrogenase (decarb-oxylating) (NADP+), glucosephosphate isomerase and phosphoglucomutase. Two markedly distinct combinations of isoenzyme patterns were seen, justifying the arrangement of the 17 stocks into two strain-groups, each of which was enzymically homogeneous. One combination was characteristic of the 11 domestic stocks of T. cruzi derived from both human infections and domiciliated animals; the second was characteristic of the six sylvatic stocks derived from opossums and a sylvatic triatomine species. The enzyme patterns were independent of the original host and the type of culture medium used. Distinction of the two strain-groups accords with epidemiological evidence that the domestic and sylvatic transmission cycles in São Felipe do not overlap. It is suggested that the diverse enzyme characters of the two strain-groups circulating in São Felipe reflect diverse origins; the domestic form of T. cruzi probably invaded the area from the south of Brazil with the domestic triatomine vector, Panstrongylus megistus.

Enzyme electrophoresis in characterizing the causative organism of Gambian trypanosomiasis

Trypanosoma (Trypanozoon) brucei includes three morphologically identical subspecies which are poorly defined by clinical behaviour; T. b. brucei does not infect man, whereas T. b. rhodesiense causes an acute, and T. b gambiense a chronic, disease. Thirty-three isolates of the complex, each of which had previously been identified on clinical or other criteria, were compared by the electrophoretic patterns of two trypanosomal enzymes, alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT). One particular ALAT pattern clearly segregated a group of human pathogens of which all except one were labelled T. b. gambiense. The exception was labelled T. b. rhodesiense, and in addition three putative T. b. gambiense isolates did not have this pattern; it is suggested that only one presents a serious anomaly. The T. b. gambiense group could also be subdivided by three ASAT patterns which coincided with known groupings based on serological criteria.

Isoenzymes of two aminotransferases among Trypanosoma vivax in Nigerian cattle

During a period of three months, thin-layer starch-gel electrophoresis was used to examine the isoenzymes of alanine and asparate aminotransferases from samples of T. vivax collected from naturally infected Nigerian cattle. Experimentally infected cattle sheep and goats were also studied. Three patterns, termed Sets 1,2 and 3, differed in both enzymes. The stability of the enzyme patterns was generally confirmed in experimental animals. The results are discussed in relation to subspeciation in T. vivax.

Diagnosis of Gambian trypanosomiasis in man by isolating trypanosomes from blood passed through DEAE-cellulose

A method is described whereby small numbers of trypanosomes in blood can be concentrated free of blood cells on to a slide. Infected blood is passed through a column of DEAE-cellulose, which adsorbs the blood cells, and the organisms are separated from the eluate by centrifugation. By this technique trypanosomes were detected in 24% of 41 Nigerian patients with suspected Gambian trypanosomiasis, but whose cervical lymph glands were not infected; of these, only 5% were positive in thick blood films. Trypanosomes were also found in 91% of 21 gland-positive patients, of which only 19% were positive in thick blood-films. The organisms could not be found in 5 patients recently treated with either pentamidine or suramin-sodium and melarsen, and disappeared within two hours from the blood of another patient given melarsoprol. Trypanosomes were not found in 3 samples of infected cerebrospinal fluid passed through DEAE-cellulose. Although 2 gland-positive patients and 1 patient with a patent parasitaemia failed to give positive results, column-separation of suspected blood is a potentially valuable aid in the parasitological diagnosis of Gambian trypanosomiasis.