On the role of the second-order derivative term in the calculation of convergent beam diffraction patterns.

The simulation of (scanning) transmission electron microscopy images and diffraction patterns is most often performed using the forward-scattering approximation where the second-order derivative term in z is assumed to be small with respect to the first-order derivative term in the modified Schrödinger equation. This assumption is very good at high incident electron energies, but breaks down at low energies. In order to study the differences between first- and second-order methods, convergent beam electron diffraction patterns were simulated for silicon at the [111] zone-axis orientation at 20 keV and compared using electron intensity difference maps and integrated intensity profiles. The geometrical differences in the calculated diffraction patterns could be explained by an Ewald surface analysis. Furthermore, it was found that solutions based on the second-order derivative equation contained small amplitude oscillations that need to be resolved in order to ensure numerical integration stability. This required the use of very small integration steps resulting in significantly increased computation time compared to the first-order differential equation solution. Lastly, the efficiency of the numerical integration technique is discussed.

Protection against Schistosoma mansoni and associated immune responses induced in the vervet monkey Cercopithecus aethiops by the irradiated cercaria vaccine.

The efficacy of the radiation-attenuated schistosome vaccine in eliciting protective immunity was investigated in the vervet Cercopithecus aethiops. Three groups of test animals received one, three, or five exposures to 5,000-9,000 cercariae attenuated with 30 krad of gamma radiation from a 137Cs source, while a fourth group served as challenge controls. After a single vaccination, no statistically significant protection was found; after three vaccinations it reached its highest peak (48%) and five exposures resulted in reduced protection (39%). Examination of immunologic parameters supported these findings, with proliferative responses of peripheral blood lymphocytes being greatest in the group vaccinated three times. Specific immunoglobulin G (IgG) levels also peaked after three vaccinations, with clear evidence of a reduction after the fourth and fifth exposures. There was a clear correlation (r = 0.66) between the antibody level at the time of challenge and the protection observed in individual vervets. These data demonstrate that protective immunity to Schistosoma mansoni can be achieved with the attenuated vaccine in a highly susceptible nonhuman primate (i.e., 82% maturation of penetrant cercariae was recorded in challenge control animals in this study). However, they also indicate that there is a ceiling to this protection. Furthermore, increasing the number of vaccinations beyond a certain point, instead of boosting protection may cause it to diminish, possibly due to the induction of immunoregulatory mechanisms.

Unusual rheumatological and cardiological manifestations of acute myelogenous leukemia in a patient with Klinefelter's syndrome.

We report the case of a 40-year-old man with Klinefelter's syndrome who presented with a complex multisystem illness, the predominant manifestations of which were rheumatological and cardiological. This disorder coincided with a diagnosis of acute myelogenous leukemia evolving out of a myelodysplastic syndrome and resolved completely after chemotherapy. It is concluded that the hematological malignancy probably played a causal role in the development of this unusual illness which was likely immunologically mediated.

Schistosome migration in primates: a study in the olive baboon (Papio anubis).

The migration of isotopically labelled schistosomula of Schistosoma mansoni from the skin to the hepatic portal system of baboons was tracked by autoradiography of compressed organ preparations. Passage of schistosomula from skin to lungs was rapid between days 2 and 5, 72% of applied parasites being detected in the lungs at the latter time. There was an equally rapid migration from lungs to liver, 60% of the adult worm burden having arrived by day 9. Perfusion data indicated a final maturation of not less than 78%. No evidence was found to support or refute a systemic phase of migration. Thus, in comparison to rodents, schistosome migration in baboons appears to be faster and more successful, possibly because the lungs do not represent a significant obstacle to migration.

Experimental transmission of Leishmania major to vervet monkeys (Cercopithecus aethiops) by bites of Phlebotomus duboscqi (Diptera: Psychodidae).

Experimental transmission of Leishmania major to vervet monkeys (Cercopithecus aethiops) was accomplished by bites of Phlebotomus duboscqi sandflies. Three-day-old, laboratory-reared P. duboscqi were fed on leishmanial lesions on hamsters infected with L. major. The flies were re-fed on monkeys 10 d after infection. Five adult male vervet monkeys were used in concurrent transmission trials. Two of the monkeys received subcutaneous inoculations with stationary-phase promastigotes (2 x 10(6) promastigotes in 0.1 ml of medium) on the base of the tail. Putatively infected P. duboscqi were allowed to feed on the remaining 3 monkeys at sites on the base of the tail and on the right eyebrow. Challenges by sandfly bites resulted in multiple leishmanial lesions at all bite sites and, consequently, more lesion area than was produced by needle challenges. Post-feeding dissection of sandflies indicated that multiple lesions could be caused by bites of a single fly, and that probing alone, without imbibing blood, was sufficient for transmission. These first experimental transmissions of L. major to vervets by bites of P. duboscqi demonstrate that sandfly challenge is an efficient alternative to needle challenge, making available a unique Leishmania-sandfly-non-human primate model for use in vaccine development.

IFN-gamma and delayed-type hypersensitivity are associated with cutaneous leishmaniasis in vervet monkeys following secondary rechallenge with Leishmania major.

IFN-gamma levels and delayed-type hypersensitivity (DTH) responses were evaluated in vervet monkeys, following secondary infection with Leishmania major (L. major). The animals had previously been vaccinated with leishmanial antigen, exposed to a primary infection and allowed to self-cure. Supernatants of peripheral blood mononuclear cell (PBMC) cultures, stimulated with either L. major antigen or Concanavalin A (Con A), were examined for the presence of IFN-gamma in a double sandwich enzyme-linked immunosorbent assay (ELISA). Significant levels of IFN-gamma were detected during active disease and following self-cure in both antigen and Con A supernatants. Higher levels of IFN-gamma were, however, present during active disease as compared with after self-cure. Positive and strong DTH responses were elicited in all experimental animals, following intradermal injection of fixed promastigotes (5 x 10(7)/animal) before rechallenge, during active infection and following self-cure. Again, strongest DTH responses were obtained during active infection as compared with the other sampling points. There was a correlation between IFN-gamma levels and DTH responses. It was concluded that IFN-gamma secretion and positive DTH responses are associated with secondary L. major infection and represent specific immunological correlates of protection in this disease model.

Nutrition, body condition, activity patterns, and parasitism of free-ranging troops of olive baboons (Papio anubis) in Kenya.

Three troops of olive baboons (Papio anubis) comprising 134 animals were captured during a translocation program. All three troops (PHG, CRIP, WBY) lived in high-altitude savannah, but two (CRIP and WBY) also frequented human settlements, where they had access to the garbage pits and vegetable gardens. The translocation offered the opportunity to compare body condition, activity patterns, and parasitism among the troops of animals. A variety of body measurements were taken, a physical examination performed, activity patterns for the previous 2 years enumerated, and blood and feces collected for virological and parasitological analyses. Body condition, as judged qualitatively by appearance and quantitatively by subcutaneous fat thickness and body weight, was lowest in PHG, the naturally foraging troop. All animals were negative for all viruses. No blood-borne parasites were found, but the feces of the majority of animals were positive for eggs of strongyles, ascarids, Trichuris spp., and Strongyloides spp. Quantification of strongyles indicated the heaviest burdens were in the non provisioned troop PHG. These results when combined with the behavioral observations that PHG spent more time foraging and less time resting or socializing than WBY suggest lowered availability and/or a poorer quality of PHG's diet. The data support the hypothesis of a causal relationship between host nutrition and helminth parasite infection but do not permit general conclusions to be drawn on mechanisms of interaction.

Structure and function of the cibarial armature in Simuliidae.

Cibarial armature morphology in adult female blackflies (Diptera: Simuliidae) is described using scanning electron microscopy. Three distinct types of armature are recognized, comprising those with teeth, e.g. Simulium ochraceum, S. ornatum, S. veracruzanum and S. vorax, those with spicules, e.g. Austrosimulium bancrofti, S. damnosum, S. exiguum, S. metallicum and S. neavei; and those lacking these projections, e.g. Prosimulium rufipes and S. lineatum. Whereas the armature is poorly developed in vectors of human onchocerciasis such as S. damnosum, S. exiguum, S. metallicum and S. neavei, the well-developed armature in S. ochraceum, S. veracruzanum and S. vorax does not prevent these species becoming infected with Onchocerca spp. (Nematoda: Onchocercidae). Hence the armature is not primarily a mechanism to counteract microfilaria superinfection. Since cibarial armatures are more developed in the haematophagous females than in the males of certain Families of flies, e.g. Ceratopogonidae, Culicidae, Phlebotominae and Simuliidae in the sub-order Nematocera, evidently the armature has evolved in response to the blood-feeding habit. As the suction of imbibed blood by the cibarial pump may require a valve mechanism to prevent back-flow, it is suggested that the armature is primarily for this purpose. Secondarily, the cibarial armature presents a damaging barrier against ingested microfilariae.

The development of Onchocerca volvulus in two temperate blackfly species, Simulium ornatum Meigen and Simulium lineatum Meigen.

In view of the promise shown by temperate simuliids for laboratory colonization, the ability of Simulium ornatum and S. lineatum to support the development of Onchocerca volvulus was investigated. An injection technique is described for the introduction of O. volvulus microfilariae from a chimpanzee into female simuliids in the absence of a bloodmeal. RPMI 1640 medium, with penicillin, streptomycin and foetal calf serum, proved satisfactory as an inoculation medium. Third stage larvae were obtained in both S. ornatum and S. lineatum after seven days at 27 degrees C. The rate of development of the parasite in S. ornatum is recorded.

Operative photography in gynaecological endosurgery.

OBJECTIVES: To define the attitude of patients, doctors and nurses to operative photographs captured at gynaecological endosurgery, and to determine the value of these photographs in patient education. DESIGN AND SETTING: Postal questionnaire survey of specialists, general practitioners, nurses and patients at a tertiary referral hospital in south-west Sydney. PARTICIPANTS: All patients who underwent endoscopic gynaecological surgery between 1 February and 1 May 1998, and for whom good quality operative photographs were available, and medical and nursing staff randomly selected from lists of practitioners within the Southwest Sydney Area Health Service. MAIN OUTCOME MEASURES: Opinions on whether operative photodocumentation assists patients in understanding their condition; the value to patients of these records; whether operative photographs assist referring doctors in subsequent management of patients; the use of operative photographs in medical records or as personal records for patients; whether photographs may lead to anxiety or be used in medicolegal action. RESULTS: All patients believed operative images were valuable in helping them understand their condition. 19 of 20 specialists (95%), 85 of 123 general practitioners (69%) and 23 of 28 nursing staff (82%) also believed that operative images assist patients in understanding their disease. Nearly all patients denied that operative images would create anxiety, and specialists, general practitioners and nurses also felt that the photographs would not cause anxiety. 78% of general practitioners expressed a desire to receive operative images. CONCLUSIONS: Photographic records of operative procedures are regarded as valuable by both referring doctors and their patients. Patients find photographs useful in understanding their disease.

Peritrophic membrane formation in three temperate simuliids, Simulium ornatum, S. equinum and S. lineatum, with respect to the migration of onchocercal microfilariae.

Engorged females of three temperate simuliid species, Simulium ornatum, S. lineatum and S. equinum, were collected immediately after their bloodfeeds from a cow host. Midguts were dissected out at selected time intervals thereafter, from two minutes to 24 hours post engorgement (p.e.) and peritrophic membrane formation observed. There was an initial rapid secretion of peritrophic membrane (PM) material from the midgut epithelium. The peritrophic membrane produced is Type 1, being formed by delamination from the entire midgut epithelium. This secretory phase continued for approximately two hours p.e. in all three species and was followed by a period of organization within the membrane. At between 12 and 24 hours p.e., the PM appeared more organized and was associated with the formation of several distinct laminae in both S. ornatum and S. lineatum, although in S. equinum it consisted of only a single homogenous layer. Both the rate of secretion and the resulting morphological appearance of the PM appeared species-specific and there was great variation in its thickness in all three species at all time intervals examined. It is suggested that microfilariae penetrate the PM during the initial period of its secretion before it has condensed to form a distinct structure. Furthermore, the migration of microfilariae may be restricted to, or enhanced by, the presence of very thin areas within the membrane where erythrocytes lie almost adjacent to the midgut epithelium.

The development of Theileria annulata in the salivary glands of the vector tick Hyalomma anatolicum anatolicum.

The development at 28 degrees C of Theileria annulata (Hissar) in the salivary glands of its tick vector, Hyalomma anatolicum anatolicum, was studied using Giemsa-stained smears, methyl green-pyronin-stained preparations of whole glands, and electron microscopy. Nymphs which had engorged on T. annulata-infected calves showed kinetes in the haemolymph from Day 7 to Day 14 post engorgement, when all ticks had completed moult. Intracellular sporonts were observed within salivary gland acini from Day 7 onwards and these developed by rapid nuclear division and cytoplasmic proliferation to form primary sporoblasts. Further development was stimulated by feeding on a rabbit or by incubation at 36 degrees C. The primary sporoblasts appeared to become organized into membrane-bound subunits. Within 48 hours of attachment to the host, or 72 hours of 36 degrees C incubation, these units dissociated to form secondary sporoblasts. The final phase of development resulted in the progressive formation of discrete, uninuclear sporozoites within these secondary sporoblasts. No morphological differences were observed in parasite maturation between the fed and incubated groups although development was retarded by at least 24 hours in the latter. In the incubated group there was also a marked decrease in the degree of synchrony of development which resulted in fewer sporozoites being present at any one time.

Regenerative amplification of 30-fs pulses in Ti:sapphire at 5 kHz.

18-fs pulses from a self-mode-locked Ti:sapphire laser are amplified to 60 microJ of energy at 4.9 kHz with chirped-pulse amplification in a Ti:sapphire regenerative amplifier. After recompression, 30-35-fs, near-transform-limited pulses are obtained.

Implications for port placement of deep circumflex iliac artery damage at laparoscopy.

A cannula injury to the deep circumflex iliac vessels led to substantial morbidity and required surgical repair. Surgeons must increase their awareness of the anatomy of these vessels and place laparoscopic ports to minimize the risk of injury. (J Am Assoc Gynecol Laparosc 6(2):221-223, 1999)

Respiratory symptoms as an indicator of undiagnosed bowel perforation following laparoscopic surgery--an observation.

Undiagnosed bowel perforation following diagnostic or operative laparoscopies is associated with significant morbidity and is indeed the primary cause of laparoscopy related mortality. The diagnosis of bowel perforation remains difficult, predominantly because of the highly varied clinical presentation. Respiratory symptoms have rarely been reported. We outline eight cases of undiagnosed bowel perforation in which the respiratory symptoms of dyspnoea and tachypnoea manifested themselves as an integral part of the clinical presentation. We believe these 'atypical' symptoms potentially further delayed the diagnosis and instigation of definitive management. Dyspnoea and other respiratory symptoms should be considered as additional warning signs of possible undiagnosed bowel perforation following laparoscopic surgery

[Diversity of the filaria of the genus Cercopithifilaria in baboons in Kenya]. / Diversité des filaires du genre Cercopithifilaria chez les babouins, au Kenya.

Several samples of subcutaneous filariae belonging to the genus Cercopithifilaria, collected from baboons in Kenya, were compared to type materials of the two species already described from baboons, C. kenyensis Eberhard, 1980, from P. anubis in Kenya, and C. degraaffi Bain, Baker et Chabaud, 1982, from P. ursinus in South Africa. Three species have been identified from Kenyan material: C. kenyensis collected in P. cynocephalus, at Kibwezi; C. narokensis n. sp., collected in P. anubis, at Narok; C. eberhardi n. sp. collected in one P. anubis (no locality given). The microfilariae--proved to be dermal for C. kenyensis and C. narokensis--are sheathed, dorso-ventrally flattened, and according to the species with or without refractile granules under the sheath. C. kenyensis, C. narokensis and C. degraaffi are very close by the adult morphology; however good discriminative characters are to be found in the structure of the body wall and the shape of the caudal extremity. C. eberhardi is a small species with primitive characters (cephalic papillae arranged in square, body not flattened dorso-ventrally and without internal lateral cuticular thickenings, tail with well developed median point and two tiny lateral lappets, one pair of distinctly precloacal papillae). The latter species resembles Cercopithifilaria parasites of Carnivorous, confirming that this genus is homogeneous despite its exceptionally large host spectrum and geographical distribution. These peculiarities seem to be related to the biology of their vectors, the ticks Ixodidae, which insure the infective filarial larvae a great longevity coupled to a wide dispersion.

The intestinal faunas of man and mountain gorillas in a shared habitat.

The primate fauna of the Impenetrable (Bwindi) Forest in southwest Uganda includes both man and the mountain gorilla Gorilla gorilla beringei. The intestinal parasite faunas of these two species were described by examining faecal samples. Of 16 parasites in the combined fauna only one, Strongyloides fuelleborni, was shared by both host species.