Anthelmintic prescribing patterns of a sample of general practitioners from selected areas in the Colombo district of Sri Lanka

General Practitioners (GPs) provide first contact care of children and pregnant mothers in the community. This study ascertained the prescribing pattern of anthelmintics to children and pregnant women by a sample of GPs from the district of Colombo. Two hundred medical practitioners engaged in full-time General Practice (100 urban and 100 rural), were selected randomly. A pre-tested interviewer-administered questionnaire was used to collect data. A total of 183 GPs aged between 26 and 72 years (median 38) participated with 94 coming from urban areas. Seventy percent of the GPs were male. Almost 13% of GPs from urban areas had a Postgraduate degree in comparison to 4.5% from the rural areas (P < 0.05). Over 50% of GPs had 6-20 years of service and over 30% treated 16-30 patients daily. Seventy-three percent of GPs from rural areas accessed health-related reading material either daily or weekly in contrast to only 40% from urban areas (P < 0.001). All GPs prescribed anthelmintics to children. Pyrantel pamoate was the preferred anthelmintic used for children by both groups. Approximately 55% and 64% of GPs from urban and rural areas, respectively, prescribed anthelmintics during pregnancy. A majority of GPs prescribed drugs after the first trimester. However, 25% from urban areas gave drugs during any trimester (P < 0.001). Regression analysis revealed that GPs with postgraduate qualifications, those having frequent access to health-related material and those seeing more than 30 patients daily, prescribed anthelmintics to pregnant women more often. Although routine de-worming of pregnant women and children should occur through government antenatal and well-baby clinics, and through the schools de-worming programme, it may not happen due to various reasons. Thus, GPs play a vital role in achieving good coverage of anthelmintics among children and pregnant women. Making available clear national guidelines on prescribing anthelmintics in Sri Lanka would improve the prescribing patterns of anthelmintics among GPs.

Impact of the 2004 mass drug administration for the control of lymphatic filariasis, in urban and rural areas of the Western province of Sri Lanka

Lymphatic filariasis is targeted to be eliminated globally, at least as a public-health problem, by 2020. The comprehensive strategy for achieving this goal includes the interruption of the transmission of the causative parasites, by drastically reducing the prevalences of microfilaraemia in at-risk communities. In a descriptive, comparative, cross-sectional and community-based study, the impact of the 2004 mass drug administration (MDA) on filarial infection, in selected areas of the Western province of Sri Lanka, has now been assessed 1-2 and 11 months after the administration of the diethylcarbamazine-albendazole combination employed. Using the cluster-sampling method, urban study populations were selected in the Colombo districts and rural ones were selected in the Gampaha district. After obtaining informed written consent, 2 ml venous blood were collected, between 20.00 and 24.00 hours, from each subject. Personal details and drug compliance in the 2004 MDA were recorded. The samples of 'night' blood were checked for microfilariae, using membrane filtration, and for filarial antigenaemia, using commercial (NOW) immunochromatographic test kits. Eighty-four (4.10%) of the 2034 subjects examined 1-2 months after the 2004 MDA but only four (0.20%) of the 1974 subjects checked 11 months after the MDA were found antigenaemic and/or microfilaraemic (P<0.001). Between the two follow-ups, the overall prevalences of both antigenaemia (4.03% v. 0.15%; P<0.001) and microfilaraemia (0.20% v. 0.05%; P=0.38) fell, although only the reduction in antigenaemia was statistically significant. The prevalence of infection (as indicated by antigenaemia and/or microfilaraemia) fell significantly within each of the two study districts (P<0.001). Although, when the prevalence of infection was high, drug compliance appeared to be an important determinant of the reduction of antigenaemia (P=0.04), the 20% difference in compliance between urban and rural areas had no apparent effect on the corresponding prevalences of infection recorded at either follow-up.

Immunodiagnosis of bancroftian filariasis

The development of immunodiagnostic tests (IDTs) for bancroftian filariasis must be aimed at defined objectives, such as the determination of exposure rates, the detection of microfilaraemia and the diagnosis of clinical filariasis. Assays for both antibody and antigen detection are necessary. Antigen determination may be more appropriate in the detection of microfilaraemia, but for clinical filariasis, antibody determination may prove more useful. The microfilarial surface antigens are very good candidates for this purpose. Determination of antibody to larval antigens may be the best way of establishing exposure rates for epidemiological purposes. An important prerequisite for IDT development is the characterization of antigens at epitope level. Sharing of antigen epitopes with host antigens could be a major limitation in IDT development. An understanding of the parasitological and immunological background of the endemic locality is also necessary. It is recommended that all IDTs are evaluated in follow-up case studies.

Correction of hyperopia by intracorneal lenses: two-year follow-up

PURPOSE

To assess the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia.

SETTING

Al-Azhar University and El Magrabi Eye Hospital, Cairo, Egypt.

METHODS

Twenty-three eyes of 21 patients who had a mean hyperopia of 4.3 diopters (D) +/- 0.71 (SD) (range +2.5 to +6.0 D) received Permavision lenses (Anamed Inc.), which are made of a highly permeable hydrogel with a water content of 78% and a refractive index close to that of corneal tissue (1.376). The Moria M2 microkeratome was used to make a 160 microm corneal flap with a diameter of +/-8.5 mm. The intracorneal lens was placed beneath the flap after minimal interface irrigation.

RESULTS

Clinical examination showed mild corneal edema and a myopic shift during the first week postoperatively. In 17 eyes (73.9%), the postoperative uncorrected visual acuity was similar to the preoperative best corrected visual acuity (BCVA); 1 eye (4.3%) lost 1 line of preoperative BCVA. In 5 eyes (21.7%), various degrees of lens opacification with some degree of corneal haze were seen after uneventful follow-up. Decentration of 0.5 to 1.0 mm was seen in 2 eyes (8.6%), 1 of which had the lens explanted because of significant opacification. Induced astigmatism was evident in 1 eye (-1.5 D). A total of 16 eyes (69.6%) were within +/-0.5 D of target, and 20 eyes (86.9%) were within +/-1.0 D (87%). No flap melting or extrusion of the lens was recorded in 24 months of follow-up. Night halos and glare were reported in 3 eyes; all had a lens diameter of 5.0 mm.

CONCLUSIONS

Intracorneal hydrogel lenses were tolerated relatively well by stromal tissue, providing a reasonably stable and predictable way to correct moderate hyperopia. However, induced astigmatism, stromal opacification, decentration, and night halos and glare occurred in a significant number of eyes. To ensure safety, deep flap cuts are preferred and these eyes should be watched carefully to avoid decentration of the lens in the early postoperative period.

Synthesis and evaluation of 2,6-piperidinedione derivatives as potentially novel compounds with analgesic and other CNS activities

New 2,6-piperidinediones 2(a-g) and 4(a-d) were prepared by initial condensation of aromatic aldehydes or cycloalkanones with cyanoacetamide to give alpha-cyanocinnamides l(a-g) or cycloalkylidenes 3(a,b) which underwent Michae1 addition with ethyl cyanoacetate or diethylmalonate. Compounds 4(a-d) were alkylated by various alkyl halides to produce the N-alkylated 2,6-piperidinedione derivatives 5(a-m). Some new selected compounds 2(a-c,f), 4(a-d) and 5(e,h,j) were pharmacologically evaluated for potential anticonvulsant, sedative and analgesic activities. These compounds exhibited significant anticonvulsant and analgesic effects after a single I.P. administration 100 mg/kg b.wt. On the other hand all the investigated compounds induced hypnotic activity and prolonged the phenobarbital sodium- induced sleep as compared with the control group and the most potent compound was found to be 2(f).

LASIK Using the NIDEK EC-5000 for the Correction of Hyperopic Astigmatism

PURPOSE

To assess the refractive outcomes of LASIK for the surgical correction of hyperopic astigmatism using the NIDEK EC-5000 excimer laser.

METHODS

LASIK was performed on 46 eyes from 26 patients (19 men and 7 women) for the correction of congenital hyperopic astigmatism. The NIDEK EC-5000 excimer laser and the Moria M2 microkeratome were used in all procedures. Cylindrical ablations were performed on the negative axis out to a 6-mm diameter.

RESULTS

The mean preoperative cylindrical refraction was +3.15+/-0.70 diopters (D) (range: +1.75 to +4.50 D), and the mean 24-month postoperative refraction was +1.27+/-0.78 D (range: +0.50 to +3.25 D). Vector analysis showed a 2.17+/-1.27 D reduction in the equivalent cylinder. Preoperative mean uncorrected visual acuity (UCVA) was 20/100, and 24-month postoperative UCVA was 20/30. One eye lost one line of best spectacle-corrected visual acuity at 24 months postoperatively. Complications related to the LASIK flap occurred in 2 (4.3%) eyes. Partial regression of the astigmatic effect began at 4 to 6 months but stabilized by 1 year.

CONCLUSIONS

LASIK is a safe but limited alternative for the correction of astigmatism in eyes with hyperopic astigmatism. Early regression of the astigmatic effect in the first 6 months seems to be the primary disadvantage of this technique.

Effects of climatic, socio-economic and behavioural factors on the transmission of hookworm (Necator americanus) on two low-country plantations in Sri Lanka

The climatic, socio-economic and behavioural factors influencing hookworm (Necator americanus) infection in Sri Lanka were explored between February 2000 and June 2001. In February 2000, a single stool sample was collected from each of the 477 subjects investigated, who were aged 2-74 years (median = 13 years) and lived on the 'lowcountry' Maliboda and Ayr plantations. The 'baseline' prevalence (28.5%) and intensity of hookworm infection (0- 4828.5 eggs/g faeces, with a mean of 128.4 eggs/g) were then determined by examining these initial samples, as Kato-Katz smears. Subsequently, each participant was treated with a single, 500-mg dose of mebendazole and then followed-up, at monthly intervals, for the next 15 months. Whenever a subject was found smear-positive for hookworm eggs at one of the monthly follow-ups, he or she was treated again with mebendazole. This approach allowed the monthly incidence of hookworm infection to be determined for each subject, assuming that subjects became smear-positive approximately 6 weeks post-infection. During the study period, rainfall and mean temperature were recorded daily and then converted to monthly values so that the relationship between the incidence of infection over each month and the rainfall and mean temperature over the same period could be explored. In addition, potentially relevant data on the socio-economic status and behaviour of each subject were collected, in questionnaire-based interviews with the adult subjects and the caregivers of the children investigated. Odds ratios (OR) and their 95% confidence intervals (CI) were then calculated for each factor that might increase the risk of hookworm infection. The monthly incidence of hookworm infection showed three peaks -- in September 2000 (21.3%), January 2001 (20.8%) and May 2001 (17.5%) -- at Maliboda, and two peaks -- in September 2000 (25.0%) and February 2001 (29.2%) -- at Ayr. With the data for all subjects combined, incidence showed a statistically significant correlation with mean temperature (r = -0.468; P = 0.018). The results of a multivariate analysis also revealed that mean temperature was significant (beta = -5.296; P = 0.01) in hookworm incidence. Bathing and washing with water from rock-pools formed by waterfalls (OR = 1.33; CI = 1.35-4.01), the use of wells (OR = 2.35; CI = 1.29-4.30), and a lack of toilets (OR = 1.60; CI = 1.01-2.53) each appeared to increase the risk of hookworm infection significantly. Those living on the two study plantations, and perhaps many other similar plantations in Sri Lanka, would clearly benefit from improved access to the public water supply (especially to pipe-borne water) and toilets.

Development of antigen-capture enzyme-linked immunosorbent assay and RT-PCR for detection of turkey astroviruses

Turkey astrovirus (TAstV) is an important agent of poult enteritis. The diagnosis of astroviruses has been dependent mainly on electron microscopy (EM) or immune EM (IEM). To develop other simple, rapid, and reliable diagnostic assays, two antigen-capture enzyme-linked immunosorbent assays (AC-ELISAs), polyclonal AC-ELISA and monoclonal AC-ELISA, were developed in this study. Monoplex and multiplex reverse transcription-polymerase chain reactions (RT-PCRs) were also developed using nondegenerate primer sets specific to the capsid region and degenerate primer pairs specific to the polymerase area of two TAstV. EM was included for comparison. Fecal or intestinal contents samples from naturally and experimentally infected poults with enteritis were examined using the developed assays. The polyclonal AC-ELISA had higher sensitivity and wider detection spectrum than the monoclonal AC-ELISA with group-specific monoclonal antibody (MAb), whereas the monoclonal AC-ELISA had very high specificity but lower sensitivity, which was estimated at 0.06 microg of viral proteins. Small round viruses (SRV) that could be astroviruses or other small viruses were detected in 34.4% of the samples examined by EM. The monoplex RT-PCR results amplified with primers SRV-1-3 and SRV-1-5 revealed that the positive rate of astroviruses was 45.3%, which was 10.9% higher than that of EM even if other SRVs were not excluded. Multiplex RT-PCR with SRV-1-3 and SRV-1-5 and AFCP-F1 and AFCP-R1 and the monoplex RT-PCR with degenerate primers verified that the positive rate of astroviruses was 59.4%, which was 25% higher than that of EM. Both RT-PCRs showed good specificity and wider detection spectrum compared with earlier published data.

Pharmacokinetics, Urinary and Mammary Excretion of Ceftriaxone in Lactating Goats

The pharmacokinetic properties of ceftriaxone were investigated in 10 goats following a single intravenous (i.v.) and intramuscular (i.m.) administration of 20 mg kg(-1) body weight. After i.v. injection, ceftriaxone serum concentration-time curves were characteristic of a two-compartment open model. The distribution and elimination half-lives (t(1/2alpha), t(1/2beta)) were 0.12 and 1.44 h respectively. Following i.m. injection, peak serum concentration (C(max)) of 23.6 microg ml(-1) was attained at 0.70 h. The absorption and elimination half-lives (t(1/2ab), t(1/2el)) were 0.138 and 1.65 h respectively. The systemic bioavailability of the i.m. administration (F %) was 85%. Following i.v. and i.m. administration, the drug was excreted in high concentrations in urine for 24 h post-administration. The drug was detected at low concentrations in milk of lactating goats. A recommended dosage of 20 mg kg(-1) injected i.m. every 12 h could be expected to provide a therapeutic serum concentration exceeding the minimal inhibitory concentrations for different susceptible pathogens.

Disposition kinetics, bioavailability and renal clearance of cefepime in calves

The pharmacokinetics of cefepime were studied following intravenous and intramuscular administration of 6.5 mg/kg in four female Friesian calves. Following single intravenous administration, the serum concentration-time curves of cefepime were best fitted using a two-compartment open model. The elimination half-life (t(1/2)beta) was 2.38+/-0.16 h, volume of distribution at steady state (Vdss) was 0.21 +/- 0.01 L/kg, and total body clearance (ClB) was 1.1 +/- 0.08 ml/min per kg. Following intramuscular administration, the drug was rapidly absorbed with an absorption half-life (t(1/2)ab) of 0.29+/-0.02 h; maximum serum concentration (Cmax) of 21.7 +/- 1.1 microg/ml was attained after (Tmax) 1.1 +/- 0.08 h; and the drug was eliminated with an elimination half-life (t(1/2)el) of 3.02 +/- 0.18 h. The systemic bioavailability (F) after intramuscular administration of cefepime in calves was 95.7% +/- 7.44%. The in vitro serum protein-binding tendency was 10.5-16.7%. Following administration by both routes, the drug was excreted in high concentrations in urine for 24 h post administration.

Wet-days: are they better indicators of Ascaris infection levels?

Seasonal variation in a particular area may influence the occurrence of helminth infections and determining such fluctuations may help to maximize the beneficial effects of mass treatment. This study determined the seasonal variations in infection levels of Ascaris lumbricoides between March 2000 and June 2001 in two selected low-country plantations. Four hundred and seventy seven persons aged between 2 and 74 years (median 13) participated. Stools were tested using the Kato-Katz method and the prevalence and intensity of infection determined. All persons were treated with a single dose of mebendazole. Monthly follow-ups were undertaken with similar stool examinations and treatment given if found positive. Infection and re-infection rates were calculated each month. Rainfall and temperature were recorded each day. Total rainfall, number of wet-days and mean temperature was calculated for each month. The prevalence of Ascaris infection was 53.4% and 51.0% at Maliboda and Ayr estates respectively. Highest infection and re-infection rates at Maliboda (37.7%, 37.2%) occurred in June and at Ayr (13.3%, 25.9%) in October 2000 respectively. During the study period, the mean rainfall was 28.1 cm (range 7.4-63.9 cm) and mean temperature 27.6 degrees C (range 22.1 degrees -34.4 degrees C). Significant correlations (P<0.05) were found between the re-infection rate and rainfall, temperature and the number of wet-days. Similar correlations were observed with the infection rate and temperature and the number of wet-days. Ascaris infections were found to correlate significantly only with the number of wet-days in a month (P<0.01). Thus, the number of wet-days appears to be a better indicator of Ascaris infections than total rainfall or mean temperature.

Pathogenicity of turkey coronavirus in turkeys and chickens

We designed this study to compare the replication potential of turkey coronavirus (TCV) and its effect in chickens and turkeys and to study the effect of singleand combined infection of turkey poults with TCV and astrovirus. We studied the pathogenicity of TCV in experimentally inoculated turkey poults and chickens by observing the dinical signs and gross lesions. Two trials were conducted with 1-day-old and 4-wk-old specific-pathogen-free turkey poults and chickens. One-day-old turkey poults developed diarrhea at 48 hr postinoculation. Poults euthanatized at 3, 5, and 7 days postinoculation had flaccid, pale, and thin-walled intestines with watery contents. The 4-wk-old turkeys had no clinical signs or gross lesions. One-day-old and 4-wk-old chicks developed no clinical signs or gross lesions although the TCV was detected in gut contents of the birds throughout the experimental period (14 days). In another experiment, mean plasma D-xylose concentrations in 3-day-old turkey poults inoculated with TCV, turkey astrovirus, or a combination of both viruses were significantly lower than in the uninoculated controls.

Correction of hyperopia with intracorneal implants

PURPOSE

To evaluate the safety and efficacy of intracorneal lenses as a surgical alternative for the correction of hyperopia.

SETTING

Al-Azhar University, Cairo, Egypt, and Louisiana State University Eye Center, New Orleans, Louisiana, USA.

METHODS

PermaVision lenses (Anamed Inc.) were implanted in the left eye of 20 albino rabbits that were followed for 6 months by confocal microscopy. The lenses are made of a highly permeable hydrogel with 70% water content and a refractive index close to that of corneal tissue (1.376). The Carriazo-Barraquer microkeratome (Moria) was used to create a 150 microm corneal flap with a diameter of 8.5 mm or larger. The intracorneal lens was placed under the flap after minimal interface irrigation.

RESULTS

At 3 days, confocal microscopy showed interface edema that resolved after 1 week. No flap melting or excursion of the lens was noted. In 1 eye, a deep lamellar keratitis was seen. At 6 months, the edge of the lens showed excellent compatibility, with no keratocytic activity or intrastromal fibrosis.

CONCLUSIONS

Intracorneal hydrogel lenses were well tolerated by stromal tissue in rabbits. They are potentially safe and can be considered as an alternative for the correction of hyperopia. Further clinical studies are required to confirm their safety in humans.

Antigenic and genomic relatedness of turkey-origin coronaviruses, bovine coronaviruses, and infectious bronchitis virus of chickens

In earlier studies in our laboratory, we found that bovine coronavirus (BCV) was pathogenic for 1-day-old turkey poults. This finding prompted us to study the antigenic and genomic relatedness of turkey origin coronaviruses (TOCVs) to BCV. A one-step reverse transcription (RT)-polymerase chain reaction (PCR) targeting a 730-base pair fragment of the nucleocapsid (N) gene of BCV and a nested PCR targeting a 407-base pair fragment of the N gene were used in an attempt to detect TOCV from North Carolina, Indiana, and a prototype turkey coronavirus (TCV) obtained from the American Type Culture Collection. Both the one-step RT-PCR and the nested PCR amplified cell culture-passaged isolates of calf diarrhea strains of BCV but none of the 15 tested TOCVs or transmissible gastroenteritis coronavirus of swine. TOCVs also did not cross-react in a BCV antigen-capture (AC) enzyme-linked immunosorbent assay (ELISA) system with monoclonal antibodies (MAbs) against N, spike glycoprotein, and hemagglutinin esterase glycoprotein proteins of BCV as coating antibodies. The same TOCVs could be detected with primers designed from the genome of infectious bronchitis virus (IBV) of chickens. These primers amplified a 1082-base pair region spanning portions of the membrane glycoprotein (M) and N protein genes of IBV and TCV. The TOCVs also cross-reacted in an AC-ELISA with MAbs against the M and subunit 2 of spike glycoprotein of IBV.

An analysis of the safety of the single dose, two drug regimens used in programmes to eliminate lymphatic filariasis

This review of the safety of the co-administration regimens to be used in programmes to eliminate lymphatic filariasis (albendazole + ivermectin or albendazole + diethylcarbamazine [DEC]) is based on 17 studies conducted in Sri Lanka, India, Haiti, Ghana, Tanzania, Kenya, Ecuador, the Philippines, Gabon, Papua New Guinea, and Bangladesh. The total data set comprises 90,635 subject exposures and includes individuals of all ages and both genders. Results are presented for hospital-based studies, laboratory studies, active surveillance of microfilaria-positive and microfilaria-negative individuals, and passive monitoring in both community-based studies and mass treatment programmes of individuals treated with albendazole (n = 1538), ivermectin (9822), DEC (576), albendazole + ivermectin (7470), albendazole + DEC (69,020), or placebo (1144). The most rigorous monitoring, which includes haematological and biochemical laboratory parameters pre- and post-treatment, provides no evidence that consistent changes are induced by any treatment; the majority of abnormalities appear to be sporadic, and the addition of albendazole to either ivermectin or DEC does not increase the frequency of abnormalities. Both DEC and ivermectin show, as expected, an adverse event profile compatible with the destruction of microfilariae. The addition of albendazole to either single-drug treatment regimen does not appear to increase the frequency or intensity of events seen with these microfilaricidal drugs when used alone. Direct observations indicated that the level of adverse events, both frequency and intensity, was correlated with the level of microfilaraemia. In non microfilaraemic individuals, who form 80-90% of the 'at risk' populations to be treated in most national public health programmes to eliminate lymphatic filariasis (LF), the event profile with the compounds alone or in combination does not differ significantly from that of placebo. Data on the use of ivermectin + albendazole in areas either of double infection (onchocerciasis and LF), or of loiais (with or without concurrent LF) are still inadequate and further studies are needed. Additional data are also recommended for populations infected with Brugia malayi, since most data thus far derive from populations infected with Wuchereria bancrofti.

Long-term efficacy of single-dose combinations of albendazole, ivermectin and diethylcarbamazine for the treatment of bancroftian filariasis

In a 'blinded' trial (in Sri Lanka, 1996-98) of 47 male asymptomatic microfilaraemic subjects with Wuchereria bancrofti infection, the safety, tolerability and filaricidal efficacy of 3 single-dose combination regimens were compared: albendazole 400 mg with ivermectin 200 micrograms/kg, albendazole 400 mg with diethylcarbamazine citrate (DEC) 6 mg/kg or albendazole 600 mg with ivermectin 400 micrograms/kg. Treated subjects were followed-up for 24 months. This represents the first long-term study using combinations of albendazole with DEC or ivermectin in the above doses against bancroftian filariasis. All subjects had pre-treatment microfilaria (mf) counts over 100/mL. All 3 treatments significantly reduced mf counts, with the albendazole-DEC-treated group showing the lowest mf levels at 18 and 24 months post-treatment. Filarial antigen tests suggested that all 3 treatments had significant activity against adult W. bancrofti; albendazole-DEC combination had the greatest activity according to this test, with antigen levels decreasing to 30.5% of pre-treatment antigen levels, 24 months after therapy. All 3 treatments were clinically safe and well tolerated. These results suggest that a single dose of albendazole 400 mg together with DEC 6 mg/kg is a safe and effective combination for suppression of microfilaraemia of bancroftian filariasis that could be considered for use in filariasis control programmes based on mass treatment of endemic populations.

Protective effect of folinic acid on low-dose methotrexate genotoxicity

INTRODUCTION

Methotrexate (MTX) is an antineoplastic agent widely used in low dose to treat patients with rheumatoid arthritis (RA). Its side effects can partly be explained by folate antagonism. Folinic acid (Leucovorin) is generally administered with MTX to decrease MTX-induced toxicity. However information regarding the inhibitory effect of folinic acid against cytogenetic damage caused by MTX is limited. The aim of this study was to assess the protective effect of folinic acid against MTX-genotoxicity.

METHODS

This study was done on Wistar albino rats and in patients with RA. Forty rats of both sexes were randomized into four equal groups and dosed in the following way: Group-I, distilled water vehicle; Group-II, 0.5 mg/kg folinic acid; Group-III, 0.5 mg/kg MTX; Group-IV, 0.5 mg/kg folinic acid plus 0.5 mg/kg MTX. Doses were given i.p., once daily for 8 consecutive days. A bone marrow chromosomal study and a micronucleus test were performed for each rat. Twenty patients with RA (5 males and 15 females) on a 10 mg weekly dose of MTX, i.m., for one month, were administered the same dose of MTX in addition to 10 mg of folinic acid as a single dose 4 hours after MTX administration, i.m., every week for another 4 weeks. Chromosomal studies as well as a micronucleus test were evaluated for each patient.

RESULTS

MTX produced a significant genetic injury as proved by the increased incidence of chromosomal aberration and micronuclei formation in Group-III animals. Inversely, folinic acid (group IV) produced a significant protection against genetic damages induced by MTX. In RA patients, folinic acid provides satisfactory improvement of MTX-induced genetic damage.

CONCLUSION

Folinic acid has a protective affect against MTX genotoxicity in human as well as in animal models.

Experimental bovine coronavirus in turkey poults and young chickens

The DB2 calf strain of bovine coronavirus (BCV) was used to inoculate 1-day-old specific-pathogen-free (SPF) turkey poults in three trials. In all trials, the birds developed clinical signs of enteritis at 48-72 hr postinoculation. Birds euthanatized at 3, 5, and 7 days postinoculation (DPI) had flaccid, pale intestines with watery contents, and the ceca were markedly enlarged with frothy contents. Coronavirus particles were detected by immune electron microscopy with BCV antibodies from the intestinal contents of birds killed at 3, 5, 7, and 12 DPI. Body weights of inoculated poults killed at 3, 5, and 7 DPI were significantly reduced as compared with controls. Hemagglutinating antibodies were detected in sera of convalescent birds at 12 DPI. However, experimental inoculation of 1-day-old SPF chicks in two trials with the same virus resulted in no clinical signs or macroscopic or microscopic lesions. No coronaviruses were detected from intestinal contents, and there were no significant differences in body weights of inoculated and noninoculated control chicks.

[Experimental corneal histological study after thermokeratoplasty with holmium laser]

PURPOSE

To analyze the histological results after application of LTK (Laser Thermal Keratoplasty). These changes explain the considerable regression of the refractive effect obtained.

METHODS

This is an experimental study in 25 eyes of albino rabbits after application of LTK, using the contralateral as a control. The histopathological evaluation was done at 12 hours, one week, one month, 3 months and 6 months of LTK spot application using various corneal stains.

RESULTS

At 12 hours there appears an intense intercellular edema and basophylia on the impact area, covering 100% of the stroma. After the first week a hyperplasia of the epithelium was found. At the first month there exists a gradual decrease of the basophylia, but the abnormal stromal structure remains. Over the third month, the collagen becomes acidophilous and with a laxer structure, thus showing the formation of new collagen. These changes remain constant at the 6th month.

CONCLUSION

The non-contact LTK induces an intense tissular damage associated to an inflammatory reaction, prior to the formation of new collagen tissue, changing the anatomic image of the cornea. These changes cause the regression of the effect produced by the holmium laser.

A preliminary analysis of Wuchereria bancrofti microfilarial antigens for potential use in diagnosis

Several antigens from the microfilarial stage of Wuchereria bancrofti have been identified using immunoblots of microfilarial antigens and screening with immune sera and tropical pulmonary eosinophilia (TPE) sera. This analysis revealed an array of antigens with apparent molecular weights of 14kDa, 35kDa, 42kDa, 63kDa, 88kDa, 97kDa and 200kDa. Among these only the 14kDa and 42kDa antigens were consistently recognized by most of the immune sera. A 132kDa antigen was recognized only by TPE sera. Analysis of rabbit immune sera revealed that the 42kDa antigen was shared by two developmental stages of W. bancrofti, namely L3 and mF. This antigen could become a potential vaccine candidate. The 14kDa antigen seems specific for the microfilarial stage and therefore could be a diagnostic marker for active infection. The 132kDa antigen could aid in the diagnosis of TPE.

Viral agents associated with poult enteritis and mortality syndrome: the role of a small round virus and a turkey coronavirus

Intestinal samples from turkey poults affected with poult enteritis and mortality syndrome (PEMS) were examined for viruses by immune electron microscopy and double-stranded RNA virus genome electropherotyping. Turkey coronavirus (TCV), avian rotaviruses, reovirus, and a yet undefined small round virus (SRV) were detected. The SRV and TCV were isolated and propagated in turkey embryos. Challenge of specific-pathogen-free turkey poults with SRV, TCV, or both resulted in mortality and clinical responses similar to those of natural PEMS. Our experiments indicate that SRV and TCV are possibly important agents in the etiology of PEMS and the combination of these infections might result in outbreaks with high mortality. The severity of clinical signs and mortality of PEMS are postulated to be partly related to the virus agents involved in individual outbreaks.

A novel synthesis of dibenzo[c,f]chromenes, dibenzo[c,h]chromenes and benzo[7,8]chromeno[3,4-f]isoindoles as antimicrobial agents

Naphtho[2,1-b]pyranone (3) was allowed to react with arylmethylenemalononitriles to yield 4-amino-5-oxo-2-aryl-5H-dibenzo[c,f]chromene-3-carbonitriles (4a,b); with ethyl 3,4-dichlorobenzylidene cyanoacetate to furnish dibenzo[c,f]chromene (5) and with elemental sulfur in dioxane containing piperidine to give thieno[3,4-d]naphtho[2,1-b]pyranone (6). Similarly, naphtho[1,2-b]pyranone (7) was reacted with arylmethylenemalononitriles and elemental sulfur to furnish dibenzo[c,h]chromenes (8) and thieno[3,4-d]naphtho[1,2-b]pyranone (10), respectively. Compound 10 underwent cycloaddition with N-arylmaleimides to yield benzo[7,8]chromeno[3,4-f]isoindoles (11a-c). Some of these compounds were screened in vitro for their antimicrobial activities.

Randomly amplified polymorphic DNA (RAPD) polymerase chain reaction assay for identification of Schistosoma mansoni strains sensitive or tolerant to anti-schistosomal drugs

The genetic differences between Schistosoma mansoni strains from different geographic areas that were reportedly resistant or sensitive to anti-schistosomal drugs were studied with randomly amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) polymerase chain reaction (PCR) assays. Of the 20 RAPD primers we chose, 19 showed the capacity to produce a medium to high level of amplification and 6 revealed difference PCR bands between drug-resistant and drug-sensitive strains. One particular primer, 5'-CAGCGACAAG-3', showed 2 major difference bands between praziquantel (PZQ)-resistant and PZQ-sensitive strains from the endemic area of Egypt. These results demonstrate that defined sequence primers could be applied as a useful tool for differentiating drug-resistant and -sensitive schistosome parasites in the field.

Re-examination of the diagnostic criteria of tropical pulmonary eosinophilia

There is no agreement on the minimum absolute eosinophil count essential for the diagnosis of tropical pulmonary eosinophilia (TPE) at present. The aim of this study was to determine this figure as well as to evaluate the other diagnostic criteria of TPE. The response to diethylcarbamazine (DEC) was tested in 98 patients [of whom 79 (80.6%) completed the study] be means of clinical scores, lung function tests and the absolute eosinophil counts. The minimum absolute eosinophil count necessary for the diagnosis of TPE was found to be 3300 for two reasons. Firstly there was a marked fluctuation in the mean percentage change of the absolute eosinophil count after treatment with DEC, when it was below 3225 cells mm-3, while the mean percentage reduction showed a remarkable stability when the eosinophil count exceeded 3600. Secondly there was a marked difference in the response to DEC in patients whose eosinophil counts were above and below these values. All patients who had eosinophil counts greater than 3600 responded to DEC and were diagnosed as cases of TPE. All of them were from filarial endemic areas. The total eosinophil count decreased by a mean of 92.5%, 3 months after administration of DEC. The sensitivities of the following tests in TPE were as follows: filarial antibody test (FAT) 30%, radiological changes 45.5%, erythrocyte sedimentation rate (ESR) 80%. The radiological changes and the ESR, but not the FAT, were helpful in differentiating TPE from those patients with TPE-like symptoms but with lower eosinophil counts, e.g. those with asthma. Patients with cough who had eosinophil counts of between 53 and 2000 cells mm-3, showed elevated filarial antibody levels in a significant number of cases when compared to asymptomatic subjects. (P < 0.001). Five of them responded to DEC. Three of these had filarial antibody in their serum and one had bilateral mottling on chest X-ray. These results suggest that atypical cases of TPE may exist. Our study has shown that the diagnosis of TPE rests on the following criteria: cough worse at night; residence in a filarial endemic area; the eosinophil count greater than 3300 cells mm-3, clinical and haematological response to DEC. The diagnosis is supported by radiological changes and elevated ESR. The FAT is of little value. The clinical benefit and the improvement in lung function which follows the administration of DEC was sustained up to a minimum period of 15 months.