Microanalysis of the Intestinal Bulb of Grass Carp (Ctenopharyngodon Idella): Histological, Histochemical, Immunohistochemical, and Scanning Electron Microscopical Studies.

Cyprinid fishes have one of the simplest types of gastrointestinal tract among vertebrates. Those fish species do not possess a true stomach that is replaced by a simple dilatation at the anterior part of the intestine called the intestinal bulb. Twenty adult specimens of grass carp were used in the present study to identify the cellular components as well as the immunohistochemical and surface architectural characteristics of the intestinal bulb. The mucosa of the intestinal bulb shows numerous, deep longitudinal folds arranged in zigzagging-like patterns. The epithelium is composed mainly of absorptive columnar cells covered by microvilli and mucous goblet cells. Spindle-shaped enteroendocrine cells and some migratory immune cells such as intraepithelial lymphocytes and rodlet cells could be identified between the absorptive cells. The epithelium also contains many secretory granules and large numbers of vacuoles containing digestive enzymes mostly in the basal part. The immunohistochemistry revealed that CD20-positive B-lymphocytes are immunolocalized mainly in the connective tissue core lamina propria of the mucosal folds. However, CD3-immunopositive T-lymphocytes are highly concentrated in the lamina propria. In addition, intraepithelial T-lymphocytes expressed immunopositivity to CD3. The current study presented many types of immune cells and suggests their essential immunological role for the intestinal blub.

Fermentative hydrogen production from low-value substrates.

Hydrogen is a promising energy source that is believed to replace the conventional energy sources e.g. fossil fuels over years. Hydrogen production methods can be divided into conventional production methods which depend mainly on fossil fuels and alternative production methods including electrolysis of water, biophotolysis and fermentation hydrogen production from organic waste materials. Compared to the conventional methods, the alternative hydrogen production methods are less energy intensive and negative-value substrates i.e. waste materials can be used to produce hydrogen. Among the alternative methods, fermentation process including dark and photo-fermentation has gained more attention because these processes are simple, waste materials can be utilized, and high hydrogen yields can be achieved. The fermentation process is affected by several parameters such as type of inoculum, pH, temperature, substrate type and concentration, hydraulic retention time, etc. In order to achieve optimum hydrogen yields and maximum substrate degradation, the operating conditions of the fermentation process must be optimized. In this review, two routes for biohydrogen production as dark and photo-fermentation are discussed. Dark/photo-fermentation technology is a new approach that can be used to increase the hydrogen yield and improve the energy recovery from organic wastes.

Effect of Melatonin on Telocytes in the Seminal Vesicle of the Soay Ram: An Immunohistochemical, Ultrastructural and Morphometrical Study.

Telocytes (TCs) are a special type of interstitial cell with characteristic cellular processes that are described in many organs. The current study aimed to investigate TCs in seminal vesicles of the Soay ram responding to melatonin treatment during the nonbreeding season by conventional immunohistochemical stains, and to detect the ultrastructural and morphometrical changes of TCs. TCs in the control group showed a broad range of staining affinity and also reacted positively to CD117/c-kit, CD34, desmin, S-100 protein, and progesterone and estrogen receptors alpha, while after melatonin treatment a strong reaction against these 6 antibodies was recorded. Electron microscopically, TCs in the control group were characterized by a small cell body with distinct long cytoplasmic extensions called telopodes (Tps). Tps had alternation of the thin segment (podomers) and dilated segments (podoms), in which the latter accommodate mitochondria, rough endoplasmic reticulum and caveolae. TCs and their Tps were interconnected by homo- and heterocellular junctions and form a wide network to communicate between different cell types. Tps showed close contact with immune cells, progenitor stem cells, smooth muscle cells and other interstitial cells. Melatonin caused a significant increase in the number of TCs, length of Tps, and number and diameter of secretory vesicles. Also, the melatonin-treated group showed exaggerated secretory activity in the form of a massive release of secretory vesicles from Tps. Moreover, Tps showed an increase in their contact with blood and lymphatic capillaries, nerve endings and Schwann cells. In addition, the shedding of secretory structures (exosomes, ectosomes, and multivesicular bodies) was greater from Tps, which were involved in paracrine signaling in the melatonin-treated group. The length and ramifications of Tps together with the intercellular junctions and the releasing of shed vesicles or exosomes assumed an essential role of TCs in intercellular signaling and coordination. On the basis of their distribution and morphology, we investigated whether the different locations of TCs could be associated with different roles.

Melatonin Elicits Stimulatory Action on the Adrenal Gland of Soay Ram: Morphometrical, Immunohistochemical, and Ultrastructural Study.

Endogenous melatonin is a hormone secreted by pineal gland; it has several roles in metabolism, reproduction, and remarkable antioxidant properties. Studies on the melatonin effect on the adrenal glands which are important endocrine organs, controlling essential physiological functions, are still deficient. In this study, we attempted to investigate the effect of exogenous melatonin treatment on the adrenal cortex and medulla using several approaches. Adrenal glands of 15 Soay ram were examined to detect the effect of melatonin treatment. Our results revealed that the cells of adrenal cortex of the treated animals were separated by wide and numerous blood sinusoids and showed signs of increase steroidogenic activity, which are evidenced by functional hypertrophy with increase profiles of mitochondria, smooth endoplasmic reticulum, and lipid droplets. The most striking ultrastructural features in the medulla of the treated group were the engorgement of chromaffin cells with enlarged secretory granules enclosed within a significantly increased diameter of these cells. The cytoplasm of these cells showed numerous mitochondria, rough endoplasmic reticulum (rER), Golgi apparatus, lysosomes, and glycogen granules. Exocytosis of secretory granules to the lumen of blood vessels was evident in the treated group. Piecemeal degranulation mode of secretion was recorded after melatonin treatment. Chromaffin cells in the control group expressed moderate immunoreactivity to Synaptophysin and tyrosine hydroxylase, compared with intensified expression after melatonin treatment. The ganglion cells of the melatonin-treated group showed a significant increase in diameter with numerous rER. The most interesting feature in this study is the presence of small granule chromaffin cells (SGC) and telocytes (TCs) for the first time in the adrenal glands of sheep. Moreover, these SGC cells, Schwann cells, fibroblasts, and progenitor stem cells showed a stimulatory response. The TCs were small branched cells scattered in the adrenal glands around cortical cells, chromaffin cells, nerve fibers, and blood vessels. These cells increased significantly in number, length of their telopodes, and secretory activity after melatonin treatment. In addition, multiple profiles of unmyelinated nerve fibers were demonstrated in all treated specimens. These results indicated that melatonin treatment caused a stimulatory action on all cellular and neuronal elements of the adrenal gland. This study may act as a new direction for treatment of adrenal insufficiency.

Dieulafoy's lesion: an overview.

Dieulafoy's lesion accounts for 1-5.8% of cases of acute upper GI bleeding. The two largest retrospective series, both from North America, found Dieulafoy's lesion as the source of hemorrhage in 1.9% and 1.2% of all endoscopies performed for acute GI bleeding. In the prospective study of Chung et al., Dieulafoy's Lesion was found in 3.4% of all patients with acute GI bleeding referred to their unit. The Dieulafoy's Lesion accounted for up to 40% of all causes of nonvariceal upper GI bleeding not caused by gastric or duodenal ulceration or esophageal varices in the prospective study of Matsui et al. In the study of Schmulewitz and Bailli, colonic Dieulafoy's Lesion were only found in 0.09% of all colonoscopies performed for lower GI bleeding. The actual incidence of both upper and lower GI bleeding from Dieulafoy's Lesion is likely higher than estimated because the diagnosis remains difficult. Recent advances in endoscopy have led to an increased detection of Dieulafoy's lesions. Initial GI endoscopy is effective in diagnosing up to 70% of patients. Several endoscopies may be required with 6% of patients, requiring three or more to establish the diagnosis. Angiography and/or red cell scanning can be used when endoscopy fails to diagnose a doubtful case. There is no definite unique policy for the treatment of Dieulafoy's lesions. Therapeutic endoscopy remains the first line of treatment option for controlling the bleeding while angiography is considered as a valuable alternative. Surgical intervention is kept for failure cases where it should be guided by preoperative localization. The mortality rate has decreased dramatically from 80% to 8.6% in recent times due to advancement in both diagnostic and therapeutic tools.

Teaching of major communicable diseases in Sudanese medical schools: a critical look.

This descriptive, cross-sectional study of Sudanese medical schools aimed to describe and analyse the proportion of their curricula currently allocated for teaching of communicable diseases and to assess the teaching methods and student assessment tools. Qualitative and quantitative data were collected from heads of departments and students in 20 of the 27 medical faculties and from ministry of health staff at federal and state levels. Curriculum designs ranged from traditional to innovative, community-oriented programmes. Problems regarding student evaluations were identified. Major limitations included shortages of staff, reference materials and teaching aids. Poor knowledge of students about different aspects of diseases endemic in Sudan was found. Recommendations include curriculum development, staff recruitment and training, and improvement of teaching and training of students.

Melatonin administration induced reactivation in the seminal gland of the soay rams during non-breeding season: An ultrastructural and morphometrical study.

Fifteen adult Soay rams were used in this experiment. Eight animals were given subcutaneous implants containing melatonin, while the other seven animals were used as control. After 11 weeks, the rams were killed and the seminal vesicles were examined by light and electron microscope. In contrast to the control grouped animals, the melatonin treated rams showed morphological, morphometrical, and ultrastructural changes as a result of reactivation of the glandular tissues of the seminal glands. The ratio of interstitial connective tissues to glandular tissues was reduced in the treated group. Melatonin induced an evident significant increase in number and height of principal cells that showed signs of increased secretory activity; apical cytoplasmic protrusions became well developed and covering the inner surface of the glandular end-pieces, also, the basal cells were significantly increased in number. The main cytological alteration in the principal cells of the seminal vesicles in treated animals was prominent increase in the concentrically arranged membranes of sER, secretory vacuoles and glycogen granules and appearance of numerous lysosomes and multivesicular bodies. Interstitial Cajal- like cells were significantly increased in number and formed a network around the epithelium and between smooth muscle cells in the treated group. The main components of these cells were mitochondria, rER, sER, and many caveolae. The cytological alterations were accompanied by subepithelial and intraepithelial nonmyelinated nerve terminals in the treated animals. The results support the view that melatonin activates and increases the secretory activity of seminal gland in sheep.

Seroepidemiology of rubella in Kuwait: an alternative vaccination policy.

1054 females of child-bearing age in Kuwait were screened for rubella antibodies. 56 or 5.4% were found seronegative. In view of this relatively low rate of susceptibility, a large-scale rubella vaccination campaign in Kuwait may not be necessary. An alternative vaccination policy is suggested.

Otitis media in Sudanese children: presentation and bacteriology.

Two hundred Sudanese children (105 males, 95 females) with otitis media (OM) were studied. Their age range was from 3 months to 15 years, with 41.5% being below 2 years of age. The presenting symptoms included ear discharge in 96% and pyrexia in 26.5% of patients. Ear ache and itching were reported in 22.5% and 7.0% respectively and impaired hearing in 7.0%. Bacterial pathogens were isolated from 115 (70.1%) of 164 cultures from children with chronic discharging ears. Organisms isolated in order of frequency were: Proteus species, Klebsiella with other coliforms, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Sixty of 84 (71.4%) cultures from children with acute OM grew pathogenic bacteria. Staphylococcus aureus and Klebsiella with other coliforms were the commonest pathogens. Proteus species and Pseudomonas aeruginosa were less frequent but beta-haemolytic Streptococcus, Streptococcus pneumoniae and Escherichia coli were the least common. Antibiotic sensitivity results show that the majority of isolates from children with discharging ears were sensitive to Gentamicin, followed by Co-trimoxazole and Streptomycin. The majority of organisms showed poor sensitivity to Ampicillin and Penicillin. The results of this study show that cotrimoxazole is the drug of choice for treating children with OM.

PIP: 200 Sudanese children (105 males, 95 females) with otitis media (OM) were studied. They ranged in age from 3 months-15 years, with 41.5% under the age of 2. The presenting symptoms included ear discharge in 96% and pyrexia in 26.5%. Earache and itching were reported in 22.5% and 7.0%, respectively, and 7.0% experienced impaired hearing. Bacterial pathogens were isolated from 115 (70.1%) of 164 cultures from children with chronically discharging ears. Organisms isolated in order of frequency were: proteus species, Klebsiella with other coliforms, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. 60 of 84 (71.4%) cultures from children with acute OM grew pathogenic bacteria. Staphylococcus aureus and Klebsiella with other coliforms were the most common pathogens. Proteus species and Pseudomonas aeruginosa were less frequent but beta-hemolytic Streptococcus, Streptococcus pneumoniae, and Escherichia coli were the least common. Antibiotic sensitivity results show that the majority of isolates from children with discharging ears were sensitive to Gentamicin, followed by cotrimoxazole and streptomycin. The majority of organisms showed poor sensitivity to ampicillin and penicillin. The results of this study show that cotrimoxazole is the drug of choice for the treatment of children with OM.

Post-endemic acute bacterial meningitis in Sudanese children.

The study describes an 18-month surveillance of the epidemiological, clinical and microbiological features of childhood acute bacterial meningitis (ABM) seven months after the end of a major epidemic of Neisseria meningitidis (MC) in Khartoum. A total of 125 children, aged one month to 14 years, who were admitted with a provisional diagnosis of meningitis/meningoencephalitis to the Children's Emergency Hospital (CEH) in Khartoum, Sudan, were prospectively enrolled in the study. Bacterial meningitis was diagnosed by direct microscopy (DM), culture or a recently introduced ELISA assay (EIA-test) in 56 children. Haemophilus influenzae (HI) and MC were the commonest causative bacteria (each accounting for 38%) and were followed by Streptococcus pneumoniae (PNC, 23%). There was a relative decrease in the proportion of HI which was found to be the leading causative bacteria in a previous study done in the same hospital during endemic situations. This was accounted for by a relative excess of MC during the post-epidemic period. Molecular analysis of two MC strains revealed that clone III-I of serogroup A (that caused an intercontinental wave of MC disease between 1983 and 1990) was still prevalent. The case fatality rate was 28.6% which is higher than that reported in Sudan (18.6%) during endemic situations; but comparable to the mortality in other African countries. Of the prognostic factors on admission, low systolic blood pressure (< 70 mmHg), hyperpyrexia (temperature > 40 degrees C) and light to deep coma correlated significantly with a fatal outcome.

Dispersions of non-covalently functionalized graphene with minimal stabilizer.

We demonstrate that functionalized pyrene derivatives effectively stabilize single- and few-layer graphene flakes in aqueous dispersions. The graphene/stabilizer yield obtained by this method is exceptionally high relative to conventional nanomaterial stabilizers such as surfactants or polymers. The mechanism of stabilization by pyrene derivatives is investigated by studying the effects of various parameters on dispersed graphene concentration and stability; these parameters include stabilizer concentration, initial graphite concentration, solution pH, and type and number of functional groups and counterions. The effectiveness of the pyrene derivatives is pH-tunable, as measured by zeta potential, and is also a function of the number of functional groups, the electronegativity of the functional group, the counterion, the relative polarity between stabilizer and solvent, and the distance from the functional group to the basal plane. Even if the dispersion is destabilized by extreme pH or lyophilization, the graphene does not aggregate because the stabilizer remains adsorbed on the surface. These dispersions also show promise for applications in graphene/polymer nanocomposites (examined in this paper), organic solar cells, conductive films, and inkjet-printed electronic devices.

Rapid diagnosis of bacterial meningitis by an enzyme immunoassay of cerebrospinal fluid.

A total of 250 cerebrospinal fluid (CSF) specimens were analyzed using a rapid enzyme immunoassay (Pharmacia Meningitis EIA-Test) (EIA) for the detection of antigens of Haemophilus influenzae type b, Neisseria meningitidis (serogroups A,B,C) and Streptococcus pneumoniae (25 selected types). The test is performed in less than 1 h and read by the naked eye. EIA and coagglutination (CoA) were compared with a constructed reference that comprised samples which were either positive by culture and/or on direct microscopy (DM), or in which there were positive results with both EIA and CoA for the bacteria covered by the assays. Using this reference for CSF samples assayed in a period between two meningococcal meningitis epidemics, the sensitivity was 0.86 for EIA and 0.69 for CoA, the specificity 0.95 (EIA) and 0.97 (CoA), the predictive value for a positive result 0.81 (EIA) and 0.87 (CoA) and, the predictive value for a negative result 0.96 (EIA) and 0.93 (CoA). Antibiotics had been given to 54% of the patients before admission. All of the 56 samples that were positive in any of the tests taken during an epidemic of group A meningococcal disease were detected by EIA; CoA was negative in 45% and culture/DM was negative in 32%. Sequential dilutions of two CSF samples from which H. influenzae type b had been isolated, showed the EIA to be 16-32 times more sensitive than CoA. With both technical feasibility and good sensitivity and specificity, the EIA seems to be useful and reliable for the rapid diagnosis of bacterial meningitis, especially in situations where pretreatment with antibiotics are likely.

Clinical features and complications of epidemic group A meningococcal disease in Sudanese children.

The clinical presentation and laboratory features in relation to short-term outcome in 118 prospectively studied Sudanese children who were admitted with meningococcal (MC) meningitis and/or septicaemia during the 1988 group A MC epidemic in Greater Khartoum are described. Their ages ranged from 25 days to 15 years (mean: 78 months) and 42% were less than 5 years old. The male:female ratio was 1.6:1. Forty (34%) came from one of the peri-urban shanty towns encircling Greater Khartoum. A history of MC immunization (A and C vaccine) was obtained in 22%, but only five children (4.8%) had the vaccine between 4 weeks and 1 year before their illness. The commonest symptoms on admission were vomiting, neck rigidity and diarrhoea. Convulsions were significantly more frequent in children under 5 years old (p = 0.0005). Fifty-six (47%) had evidence of malnutrition. In descending order, fever, neck stiffness and Kernig's sign were the most commonly observed signs, the latter two being significantly more often detected in children older than 1 year. Twenty-four patients 20%) had disturbed consciousness. The case fatality rate was 6.3% and this was significantly higher in those presenting with meningococcal septicaemia (p = 0.0006). Other significant associations with mortality were short duration (less than 1 day) of symptoms (p = 0.0006) and clinical shock detected on admission p = 0.003). Transient complications were infrequent and permanent neurological sequelae were confined to bilateral profound sensorineural hearing loss in three children (2.9%) and hemiplegia in two 1.9%.(ABSTRACT TRUNCATED AT 250 WORDS)

Features of a large epidemic of group A meningococcal meningitis in Khartoum, Sudan in 1988.

A large epidemic (February-August 1988) of group A sulphonamide resistant, clone III-1 meningococcal meningitis in Khartoum, Sudan is described. A total of 10,099 cases were admitted to treatment centers with 8,397 cases during March and April, corresponding to an annual incidence of 1,679/100,000 inhabitants during this period. The age profile showed a high morbidity in adults (31% of the cases greater than or equal to 20 years). The male dominance was marked especially in the adult cases with a proportion of 3.2:1. The epidemic started during the hot and dry season and declined when the clouds came, humidity rose, temperature fell and a mass vaccination campaign had been implemented together with other epidemic precautions. Vaccination with a combined group A/C polysaccharide vaccine had been given 4 weeks-1 year before hospitalization to 11% of the children, 80% of whom were greater than 18 months of age. The estimated case fatality rate was 6.3%. Since 47% of the cases came from periurban and rural areas, the actual mortality during the epidemic might have been higher when considering those who may have died before reaching any of the treatment centres. Fatal cases had a short history of acute illness and a septic condition. Septicaemia was rare and seen in only 3.7% of the cases, the rest had acute purulent meningitis. Hearing loss/impairment and hemiplegia was diagnosed in 2-3% of the cases. The epidemiology, based on detailed typing/subtyping and restriction enzyme patterns of meningococcal strains, was apparently associated with the Mecca outbreak in August 1987.

Viral pathogens and clinical manifestations associated with acute lower respiratory tract infections in children of the Sudan.

BACKGROUND: Incomplete knowledge regarding the viral agents causing respiratory infections in children living in developing countries impedes diagnosis and management of patients. OBJECTIVES: To assess the role of viral pathogens in Sudanese children presenting with acute lower respiratory tract infections (ALRI). STUDY DESIGN: The study population consisted of patients presenting with ALRI at the Children's Emergency Hospital in Khartoum during 2 periods (December 1987 to April 1988 and September 1990 to March 1991). Identification of viral infections was based an antigen detection by immunofluorescence and enzyme-linked immunosorbent assay (ELISA) on nasopharyngeal secretions and/or serology. RESULTS: After exclusion of children with measles, 102 and 111 children, respectively, were prospectively enrolled in the study during the 2 periods. Their ages ranged between one mouth and 14 years (mean 2.0 years). Radiologic pulmonary infiltrations were detected in 135 (66%) of the 206 patients who had chest radiographs, whereas 7 (3%) showed lobar pneumonia. The case fatality rate was 2.3%. Of 83 virus infections detected, 79 were in children < years and consisted mainly of respiratory syncytial virus (RSV, 28%), followed by parainfluenza (7%), adenovirus (5%) and influenza A (2%). Infiltrates on radiographs were significantly less often found in virus-infected cases than in ALRI-cases with negative virus tests. CONCLUSIONS: RSV predominantly infected young infants (

Teaching of major communicable diseases in Sudanese medical schools: a critical look

This descriptive, cross-sectional study of Sudanese medical schools aimed to describe and analyse the proportion of their curricula currently allocated for teaching of communicable diseases and to assess the teaching methods and student assessment tools. Qualitative and quantitative data were collected from heads of departments and students in 20 of the 27 medical faculties and from ministry of health staff at federal and state levels. Curriculum designs ranged from traditional to innovative, community-oriented programmes. Problems regarding student evaluations were identified. Major limitations included shortages of staff, reference materials and teaching aids. Poor knowledge of students about different aspects of diseases endemic in Sudan was found. Recommendations include curriculum development, staff recruitment and training, and improvement of teaching and training of students