Streptococcus, Centrocestus formosanus and Myxobolus tilapiae concurrent infections in farmed Nile tilapia (Oreochromis niloticus).

Stress triggered concurrent microbial/parasitic infections are prevalent in earthen pond based farmed Nile tilapia Oreochromis niloticus. In the current study, a total of thirty five O. niloticus were collected from a commercial fish farm with a history of severe mortalities at Port Said, Egypt. Nile tilapia samples were subjected to bacteriological, parasitological and pathological examinations. Twenty one Enterococcus fecalis and 15 Streptococcus agalactiae isolates were presumptively identified utilizing the semi-automated API 20 Strept test kit. The identities of the retrieved bacteria were confirmed by the sequencing of 16 S rRNA gene. Moribund O. niloticus were found to be heavily infected by one or both of Centrocestus formosanus encysted metacercariae (EMC) and/or Myxobolus tilapiae spores presenting a unique form of synergistic and/or symbiotic relationship. The identities of both parasites were confirmed through morphological and molecular characterization. Variable circulatory, degenerative, necrotic and proliferative changes were also noticed in hematopoietic organs. Interestingly, multiple myxobolus spores and EMC were noticed in some histological sections. It was obvious that the current concurrent bacterial and parasitic infections are triggered by the deleterious effects of some stressing environmental conditions. The unfavorable climatic conditions (high temperature and high relative humidity) recorded at the surge of mortalities are probable predisposing stress factors.

The pathogenesis of post kala-azar dermal leishmaniasis from the field to the molecule: does ultraviolet light (UVB) radiation play a role?

Post kala-azar dermal leishmaniasis (PKDL) is a dermatosis caused by persistence of Leishmania donovani parasites in the skin following apparently successful treatment of visceral leishmaniasis. The distribution of PKDL lesions in Sudanese patients often mirrors the clothing habits of those affected. It is most severe in or confined to the sun-exposed parts of the skin. It is well established that elimination of Leishmania parasites requires activation of parasitised macrophages by a Th1 immune response and that the latter is depressed by ultraviolet light (UVB). In this paper, we hypothesized that UVB light might be a key player in the pathogenesis of PKDL. This paper links observations made in the field with immunological data that are compatible with this hypothesis. We therefore investigated patients with PKDL immunologically for a possible role of UVB exposure in the pathogenesis of this condition. We marshal evidence that the changes in the tissues are compatible with the effects of UVB light and it is probable that UVB appears to be a key factor in the pathogenesis of PKDL. Immunopathologically the lesions were characterized by an influx of various inflammatory cells. The number of CD1a (Langerhans' cells) was decreased, they lost their dendrites, their HLA-DR and B7-1 expression was down regulated while B7-2 was expressed. Others have shown that Langerhans' cells with these features result from UVB exposure and that such cells are unable to present antigen to Th1 cells while retaining the capacity to present antigen to Th2 cells. Various cytokines known to be induced by UVB radiation could be demonstrated in PKDL lesions. Of these IL-10, TGF-beta, IL-12, IL-4 and TNF-alpha were found in different quantities. The Th-1 cytokine IFN-gamma was constantly present. The tissue origin of the Th-1 cells in PKDL is unknown. We believe that the antagonistic action of the different cytokines is the cause of the inflammation and chronicity of PKDL.

Ultrastructural changes in rat livers perfused in vitro and in vivo with a high dose of methotrexate.

Methotrexate is an antifolate that is widely used in the treatment of malignant tumours and other diseases. The present study was undertaken to examine the short-term effects of high doses of methotrexate (HD-MTX) on the ultrastructure and metabolic activity of isolated rat livers. The authenticity of the drug-induced changes was substantiated by the concomitant use of in vivo experiments. Isolated rat livers were infused with HD-MTX via the portal vein for 3 hours (total dose for each liver 2000 mg). For in vivo experiments, each rat received a single intravenous injection of a maximum tolerated dose of MTX (100 mg/kg body weight) that allowed the animals to survive for 3 days. At the end of each experimental period, MTX-treated and control livers were processed for light microscopy (LM), scanning (SEM) and transmission electron (TEM) microscopy. Oxygen consumption and thyroxine metabolism were measured in treated and control isolated livers. With the exception of a few minor differences, the structural changes in the hepatocytes after MTX treatment in vitro and vivo were similar. There were focal changes consisting of disruption of normal hepatic plates and swelling and vacuolation of the hepatocytes, with no clear evidence of restriction to a specific hepatic zone. SEM revealed striking changes in the plasma membrane, the microvillar system, intercellular junctions and the sinusoidal endothelium. TEM revealed disorganized endoplasmic reticulum, dispersion of the polyribosomes, a variety of mitochondrial changes, and glycogen redistribution. In MTX-treated isolated rat livers, the uptake of tetraiodothyronine (T4) was not affected, but triiodothyronine (T3) release was impaired. Oxygen consumption was increased in livers treated with MTX. Employing an organotypic liver perfusion model in conjunction with the in vivo experiment and the use of SEM, TEM and hepatic thyroxine measurements, this investigation revealed that infusion of HD-MTX induced early ultrastructual changes in cell membrane, intercellular junctions and cell organelles and disturbance in the functional integrity of the hepatocytes in isolated rat liver.

Eleven years of malaria surveillance in a Sudanese village highlights unexpected variation in individual disease susceptibility and outbreak severity.

An analysis is presented of continuous data collected over 11 years based on 1,902,600 person/days of observation on the malaria experience of the people of Daraweesh, a village in eastern Sudan. Malaria transmission is hypo-endemic: the acquisition of clinical immunity with age is not as obvious as in more holo-endemic areas and malaria remained a problem in all age groups throughout the study. However, this population, who are of Fulani origin, showed a distinctly variable level of disease susceptibility. Thirty-two percent of the village never reported malaria symptoms or required malaria treatment while others experienced up to 8 clinical episodes over the 11 years of observation. Malaria incidence was clearly influenced by drought but much less obviously by rainfall. To what extent outbreak patterns are explicable in terms of anopheline factors, and to human immune factors, remains an interesting question for malaria modelling in this, and in other low transmission zones, such as the burgeoning urban areas of modern Africa.

Assessment of women's satisfaction with medical termination of pregnancy.

This was a prospective study involving 205 women seeking medical abortion with gestational age

Post-kala-azar dermal leishmaniasis.

Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL); it is characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well. The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity. It is mainly seen in Sudan and India where it follows treated VL in 50% and 5-10% of cases, respectively. Thus, it is largely restricted to areas where Leishmania donovani is the causative parasite. The interval at which PKDL follows VL is 0-6 months in Sudan and 2-3 years in India. PKDL probably has an important role in interepidemic periods of VL, acting as a reservoir for parasites. There is increasing evidence that the pathogenesis is largely immunologically mediated; high concentrations of interleukin 10 in the peripheral blood of VL patients predict the development of PKDL. During VL, interferon gamma is not produced by peripheral blood mononuclear cells (PBMC). After treatment of VL, PBMC start producing interferon gamma, which coincides with the appearance of PKDL lesions due to interferon-gamma-producing cells causing skin inflammation as a reaction to persisting parasites in the skin. Diagnosis is mainly clinical, but parasites can be seen by microscopy in smears with limited sensitivity. PCR and monoclonal antibodies may detect parasites in more than 80% of cases. Serological tests and the leishmanin skin test are of limited value. Treatment is always needed in Indian PKDL; in Sudan most cases will self cure but severe and chronic cases are treated. Sodium stibogluconate is given at 20 mg/kg for 2 months in Sudan and for 4 months in India. Liposomal amphotericine B seems effective; newer compounds such as miltefosine that can be administered orally or topically are of major potential interest. Although research has brought many new insights in pathogenesis and management of PKDL, several issues in particular in relation to control remain unsolved and deserve urgent attention.

Bisphosphonate space measurement and dosage requirement for intravenous clodronate treatment of Paget's disease.

It has been claimed that the bisphosphonate space, a scintigraphic technique which simultaneously estimates bone uptake and renal clearance of bisphosphonate, can be used to predict the dose of bisphosphonate required to induce biochemical remission in Paget's disease. In a prospective study of 15 newly diagnosed patients with Paget's disease, bisphosphonate space measurements were made prior to treatment with intravenous clodronate. Treatment with clodronate 0.6 g was given four times weekly until the alkaline phosphatase (ALP) suppressed below the upper level of the reference range (120 u/l) or reached a plateau, and the cumulative dose required (1.8-7.8 g) was calculated. Overall, the bisphosphonate space correlated poorly with the total dose requirement (r = 0.441, P = 0.100), but the relationship was weakened by an outlier, who had the poorest renal function. Excluding this subject improved the correlation coefficient (r = 0.852, P <0.0001). The relationship between dose requirement and log10 initial ALP was not as strong (r = 0.672, P <0.01). However, for both ALP and the bisphosphonate space the 95% prediction intervals were wide. We conclude that the bisphosphonate space does relate to dose requirements for intravenous bisphosphonates, but that it is unreliable when renal function is poor, and may not offer much gain over the pretreatment ALP levels. Both ALP and the bisphosphonate space have wide prediction intervals, and are therefore poor guides to dose requirement.

"FUR"--one size suits all.

This work used amalgamated data from previous projects in order to test the concept that when organ function is expressed in terms of tracer kinetics, the results are independent of patient size or gender. Dynamic gamma camera studies were analysed by measuring the rate of movement of tracers from the blood into various organs. These rates were expressed as a "fractional uptake rate" (FUR), which is the fraction of tracer in the blood taken up by the organ per unit time. As these values were small, it was convenient to express the FUR per million seconds. The FUR was calculated using the expression FUR = SLOPE (of Rutland-Patlak plot), multiplied by B(0) (the blood curve value back-extrapolated to time zero), and divided by the TOTAL amount of tracer injected. Data were used from adult patients between the ages of 20 and 49 years who had normal organ function. Organ/tracer groups studied were the skeletal uptake of 99mTc-MDP, the renal uptake of 99mTc-MAG3, the renal uptake of 99mTc-MDP, the renal uptake of 99mTc-DTPA, the hepatic uptake of 99mTc-colloid, the splenic uptake of 99mTc-colloid, and the hepatic uptake of 99mTc-DISIDA. Each organ/tracer group was divided into three subgroups according to patient size (smallest, middle and largest), and also into subgroups according to gender. Comparison of these subgroups did not show any significant size- or gender-related differences in FUR values. It is concluded that for patients with normally functioning organs the FUR is independent of patient size or gender. Thus, the FUR is a valuable way of expressing organ function, particularly in patients with unusual or rapidly changing body size, such as children.

Chronic Plasmodium falciparum infections in an area of low intensity malaria transmission in the Sudan.

Chronic Plasmodium falciparum malaria infections in a Sudanese village, in an area of seasonal and unstable malaria transmission, were monitored and genetically characterized to study the influence of persistent infection on the immunology and epidemiology of low endemicity malaria. During the October-December malaria season of 1996, 51 individuals out of a population of 420 had confirmed and treated P. falciparum malaria in the village of Daraweesh in eastern Sudan. In a cross-sectional survey carried out in December 1996, an additional 6 individuals were found to harbour a microscopically negative but polymerase chain reaction (PCR)-positive P. falciparum infection. On 1 January 1997, a cohort of 43 individuals aged from 9 to 53, recruited from this group of recently malaria-infected individuals agreed to donate fortnightly blood samples for the next 9 months, the first 6 of which constitute the long Sudanese dry season when transmission falls to undetectable levels. Each blood sample was tested for the presence of persistent malaria infection by microscopy and PCR. Parasite-positive samples were genotyped using PCR assays that detect allelic polymorphism at the MSP-1, MSP-2 and GLURP marker gene loci. Of 43 individuals 16 were found to maintain chronic P. falciparum infections which were continuously genetically characterized.

Left ventricular ejection fraction and volumes calculated from dual gated SPECT myocardial imaging with 99Tcm-MIBI.

Dual gated (DG) cardiac single photon emission computed tomographic (SPECT) studies at end-diastole (ED) and end-systole (ES) were acquired in 27 ischaemic heart disease (IHD) patients after intravenous injection of 555-740 MBq 99Tcm-MIBI. Acquisition parameters were: 180 degrees from LPO to RAO, 32 projections, 64 x 64 matrix, 75 cardiac beats per projection, 80 ms at ED and 80 ms at ES for each cardiac cycle. A computer program was developed to calculate the ED and ES left ventricular (LV) volumes and LV ejection fraction (EF). The computational approach is interactive, semi-automatic and iterative with built-in visual quality control. Short axis slices are used with corresponding ED and ES slices processed as pairs from apex to base. Left ventricular cavity pixels are identified and summed on a slice-by-slice basis. Myocardial pixels are similarly identified. The computed LVEF and ED and ES volumes have been correlated with those from contrast ventriculography (CV). The mean calculated EF for 27 patients was 53.6 +/- 10.7% from DG SPECT versus 55.3 +/- 12.1% from CV (NS). The EF linear correlation coefficient was r = 0.97.

Iatrogenic obstructive jaundice caused by the balloon of a Foley catheter. Case report.

A rare kind of obstructive jaundice caused by compression on the common bile duct due to an inflated Foley catheter balloon placed in the duodenum after Suguira surgery for bleeding esophageal vesicles secondary to portal hypertension is presented. After deflating the balloon, the obstruction was relieved. Tc-99m HIDA studies were helpful in the diagnosis of obstruction of the common bile duct and the response following the deflation.

Implementation of the T4/5 left ventricular functional image on a VAX-based Lexidata image processing station.

A VAX-based Lexidata image processing station has been used for the development and application of image processing and data analysis techniques in nuclear medicine. Within the area of cardiac multigated equilibrium blood-pool scintigraphy, the computational implementation of the T4/5 functional image, a new left ventricular functional image, is presented. This image reflects myocardial compliance. The versatility of the implementation is demonstrated. Examples of the T4/5 functional image are presented. The VAX-based Lexidata image processing station is a useful tool for parameter, feature, and image extraction from nuclear medicine images.

Population estimation of Riyadh City using aerial photography.

PIP: Two sets of aerial photographs of Riyadh, Saudi Arabia, taken in 1968 and 1983 are used to estimate population size and growth during the period. The estimates are compared with census data and official forecasts and are shown to be within four percent of the official estimates of population size.^ieng

Plasma chloroquine measurement in the evaluation of Plasmodium falciparum sensitivity.

In-vivo assessment of the sensitivity of Plasmodium falciparum to chloroquine was carried out in 63 patients in eastern Sudan. Standard triple-dose therapy with chloroquine (25 mg base kg-1 body wt) failed in curing 30 patients. All grades of resistance were demonstrated in the study, confirming that the phenomenon of chloroquine resistance is well established in this area. Factors which may have accelerated the spread of resistant strains include: a drop in the immunity of the local people caused by previous drought, introduction of non-immune refugees, increased transmission following heavy rains, and massive drug pressure. Plasma levels of chloroquine attained in our patients exceeded the therapeutic level and thus ruled out ineffective levels as a possible cause of treatment failure. Moreover, there was no significant difference between chloroquine levels in patients infected with sensitive or resistant strains. As some patients were cured with an additional dose of chloroquine, it is proposed that chloroquine measurement be carried out in patients treated for falciparum malaria with a view to defining new effective levels for semi-immune populations.

Survey of residues of organochlorine pesticides in some marketable Egyptian fish.

One hundred random samples representing 34 species of marketable fish were collected from 8 Egyptian governorates during the period March 1986 to March 1988 and were analyzed for the presence of some organochlorine pesticides. The results showed the predominance of beta-BHC and lindane at maximum levels of 435.30 and 59.00 micrograms/kg, respectively, for fish samples obtained from Damietta governorate. The corresponding levels of aldrin, and o,p'-DDT were 34.27 and 734.10 micrograms/kg, respectively, for fish from the Red Sea governorate. gamma-Chlordane, p,p'-DDE, and p,p'-DDT were found in fish from Ismailia governorate at respective maximum levels of 36.17, 234.40, and 57.19 microgram/kg. Heptachlor was identified at 8.50 micrograms/kg in Port Said governorate fish and o,p'-DDE at 10.59 micrograms/kg in Suez governorate fish. Mirex, on the other hand, could not be detected in any of the samples investigated.

Segmental analysis of SPECT 99mTc-methoxy isobutyl isonitrile and 201Tl myocardial imaging in ischaemic heart disease.

To study the potential usefulness of 99mTc-methoxy isobutyl isonitrile (99mTc-MIBI) as a substitute for 201Tl in assessing patients with ischaemic heart disease, 24 patients underwent 1 day rest and exercise 99mTc-MIBI single photon emission computerised tomography (SPECT) 1 week after SPECT exercise 201Tl. All patients were catheterized within 1 month after myocardial imaging. In 17 patients, resting first pass radionuclide angiography (FPRNA) was performed with 99mTc-MIBI. The heart to lung ratio for 99mTc-MIBI and 201Tl was calculated both at rest and exercise. The segmental analysis for myocardial perfusion reveals that 87/96 segments (91%) were correctly classified by SPECT 201Tl and 84/96 segments (88%) were correctly classified by 99mTc-MIBI. A significant correlation was present between LVEF measured by 99mTc-MIBI FPRNA and contrast ventriculography (r = 0.85, P less than 0.0001). The heart to lung ratio both at rest and exercise for 99mTc-MIBI is significantly higher than 201Tl (P less than 0.01 and less than 0.001 respectively). We conclude that 99mTc-MIBI is a promising agent for simultaneous evaluation of myocardial perfusion and cardiac function.

Factors affecting the Gates' measurement of glomerular filtration rate.

The following technical factors affect the Gates' measurement of glomerular filtration rate (GFR): 1) net injected activity, 2) kidney depth, 3) corrected kidney counts. In the syringe measurement prior to injection, self-attenuation causes 16% data loss for a volume of 0.5 ml if the syringe is positioned perpendicular to the collimator face. A +/- 1 cm error in true kidney depth may cause a 16% difference in GFR in an adult. The choice of the background region of interest (ROI), for background subtraction significantly affects the calculation. To minimize errors in the Gates' estimate of GFR we recommend 1) that syringe counting be done with the syringe parallel to the collimator face; 2) that the i.v. set be included in the postsyringe measurement; in cases of extravasation, the injection site should also be counted; 3) that kidney depth, especially for ectopic and transplanted kidneys be estimated by ultrasound or using lateral views; and 4) that a background ROI for each kidney be used.