Phenotypic characterisation of Saccharomyces spp. for tolerance to 1-butanol.

Biofuels are expected to play a role in replacing crude oil as a liquid transportation fuel, and research into butanol has highlighted the importance of this alcohol as a fuel. Butanol has a higher energy density than ethanol, butanol-gasoline blends do not separate in the presence of water, and butanol is miscible with gasoline (Szulczyk, Int J Energy Environ 1(1):2876-2895, 40). Saccharomyces cerevisiae has been used as a fermentative organism in the biofuel industry producing ethanol from glucose derived from starchy plant material; however, it typically cannot tolerate butanol concentrations greater than 2 % (Luong, Biotechnol Bioeng 29 (2):242-248, 27). 90 Saccharomyces spp. strains were screened for tolerance to 1-butanol via a phenotypic microarray assay and we observed significant variation in response with the most tolerant strains (S. cerevisiae DBVPG1788, S. cerevisiae DBVPG6044 and S. cerevisiae YPS128) exhibiting tolerance to 4 % 1-butanol compared with S. uvarum and S. castelli strains, which were sensitive to 3 % 1-butanol. Response to butanol was confirmed using traditional yeast methodologies such as growth; it was observed that fermentations in the presence of butanol, when using strains with a tolerant background, were significantly faster. Assessing for genetic rationale for tolerance, it was observed that 1-butanol-tolerant strains, when compared with 1-butanol-sensitive strains, had an up-regulation of RPN4, a transcription factor which regulates proteasome genes. Analysing for the importance of RPN4, we observed that a Δrpn4 strain displayed a reduced rate of fermentation in the presence of 1-butanol when compared with the BY4741 background strain. This data will aid the development of breeding programmes to produce better strains for future bio-butanol production.

Effects of vinblastine on calcium distribution pattern and Ca2+,Mg(2+)-adenosine triphosphatase in rat incisor maturation ameloblasts.

Vinblastine is known to affect secretory and transport functions of ameloblasts. The effects of vinblastine on distribution patterns of membrane-associated calcium and Ca2+,Mg(2+)-ATPase in maturation ameloblasts were investigated cytochemically. The potassium pyroantimonate (PPA) method was used for localizing calcium and a modified Wachstein-Meisel medium was used to localize Ca2+,Mg(2+)-ATPase. Ultrastructural changes induced by vinblastine included dislocated organelles and reduction or elimination of the ruffled border of the ameloblasts. Membrane-associated calcium pyroantimonate deposits were markedly reduced. The intensity of Ca2+,Mg(2+)-ATPase reaction product was also markedly reduced by vinblastine. Concomitant reduction of membrane-associated calcium and Ca2+,Mg(2+)-ATPase lends support to a role for maturation ameloblasts in control of a cyclic pattern of influx of calcium to mineralizing enamel.

Cytochemical localization of calcium and Ca2+,Mg2(+)-adenosine triphosphatase in colchicine-altered rat incisor ameloblasts.

Colchicine is known to affect secretory, transport, and degradative functions of ameloblasts. The effects of colchicine on membrane-associated calcium and Ca2+,Mg2(+)-ATPase in secretory and maturation ameloblasts were investigated cytochemically. The pyroantimonate (PPA) method was used for localizing calcium and a modified Wachstein-Meisel medium was used to localize Ca2+,Mg2(+)-ATPase. Sections representing secretory and early maturation stages were examined by transmission electron microscopy. Morphological changes induced by colchicine included dislocated organelles and other well-established reactions to such anti-microtubule drugs. Calcium pyroantimonate (Ca-PA) deposits in most ameloblast types were markedly reduced, with the greater reduction occurring in those cells more severely altered morphologically. However, the cell membranes of both control and experimental smooth-ended maturation ameloblasts were essentially devoid of Ca-PA. The normal distribution and intensity of Ca2+,Mg2(+)-ATPase was not affected by colchicine. Because the observed reduction of membrane-associated calcium is apparently not mediated by Ca2+,Mg2(+)-ATPase in this case, other aspects of the calcium regulating system of ameloblasts are apparently targeted by colchicine.

Virologic and serologic surveillance for dengue fever in Jeddah, Saudi Arabia, 1994-1999.

Dengue fever infection was first documented in Jeddah, Saudi Arabia, by virus isolation of dengue type 2 virus in 1994 at the virology laboratory of Dr. Soliman Fakeeh Hospital. Dengue virus surveillance was established after that time. Blood samples were collected from 985 patients (710 male patients and 275 female patients) with suspected cases of dengue from February 1994 to December 1999. Dengue virus isolates were obtained in 207 patients (21%; 162 male patients and 45 female patients). Dengue type 2 was the predominant serotype (138 of 207 isolates, 66.7%), followed by dengue type 1 with (56 of 207 isolates, 27%) and dengue type 3 (13 of 207 isolates, 6.3%). The largest number of isolates (186 of 207 isolates, 90%) was in 1994, a year during which there was a dengue epidemic. In the next 5 years, 1995-1999, only 21 isolates (10%) were isolated. Immunoglobulin M capture enzyme-linked immunosorbent assay was positive in 160 acute samples; 52 of them were from virus culture-positive cases and 108 (11%) from culture-negative cases. The total number of cases diagnosed by both methods was 315 (32%). The prevalence of dengue immunoglobulin G antibodies, as assessed on the basis of immunofluorescent assay, hemagglutination inhibition titers > or = 1/20, or both, in the acute samples was 314 (32%) of 985, indicating past Flavivirus infection. Two patients died, one man with dengue hemorrhagic fever and one woman with dengue shock syndrome. Both fatal dengue cases were due to infection with type 2 virus. All other cases were simple dengue fever. To our knowledge, this is the first report confirming the circulation of 3 dengue serotypes in Jeddah.

Hepatitis C: prevalence and common genotypes among ethnic groups in Jeddah, Saudi Arabia.

The presence of antibodies to hepatitis C virus (HCV) was examined using a third-generation ELISA in 3,350 serum samples obtained from patients visiting different outpatient clinics, preoperative patients, and women visiting for ante-natal care at the Dr. Fakeeh hospital in Jeddah, Saudi Arabia from January to September 1998. The population included mainly Saudis, Egyptians, and Yemenis, and patients from other Middle East and Asian countries. The prevalence of HCV infection was 5.87% among Saudis, 22.54% among Egyptians, and 2.12% among Yemenis. The prevalence among patients from other Middle East and Asian countries were 3.38% and 4.98%, respectively. The overall prevalence among the studied group was 6.75%. Genotyping of isolates from Saudi Arabia showed that the prevalences of types 4, la, 1b, and 2 were 45.9%, 40.6%, 10.85%, and 2.7%, respectively. Genotyping of isolates from Egypt showed that type 4 was the major type among Egyptians (91.6%), while types 1a and 1b each had prevalences of 4.2%.

The incidence of diarrheal disease in a defined population of rural Egypt.

A prospective study of diarrheal illness was conducted for 2 years in 309 families who were part of an epidemiologic research center population in rural Egypt. The rates of illness peaked in the first year of life with between 5 and 6 episodes per person year at risk. Although no seasonal variation in reported diarrhea was demonstrated for the total population, age-specific differences in seasonal occurrence were noted. The incidence did not consistently vary by village size, nor did rates vary by sex.

The detection of enteropathogens in acute diarrhea in a family cohort population in rural Egypt.

In 8 villages of rural northeastern Egypt, a 2-year study of the etiologic agents associated with episodes of diarrhea was carried out. Stool specimens (3,243) from 3,513 episodes of diarrhea were processed for enteropathogens. The most commonly identified agents in the group with diarrhea were Giardia lamblia (44%), heat stable enterotoxin (ST)-producing enterotoxigenic Escherichia coli (ETEC) (15%), heat labile toxin (LT)-producing ETEC (12%), enteropathogenic E. coli (EPEC) (4%), rotavirus (3%), Shigella (2%) and Salmonella (1%). Isolation rates were increased in cases compared to controls for all agents except G. lamblia and EPEC strains. Rotavirus, Salmonella and ST-producing ETEC were more frequently isolated during cooler months and Shigella and LT-ETEC occurred more commonly in warmer months. Campylobacter, EPEC, Giardia and E. histolytica did not show a discernable seasonal pattern. Rotavirus was primarily associated with diarrhea in infants only. Forty-four percent of children experienced at least 1 bout of rotavirus diarrhea by the age of 3 years. Vomiting was reported in 65% of cases of rotavirus infection. Dehydration was reported in greater than 40% of those with rotavirus-, Salmonella-, Campylobacter-, LT-ETEC- and EPEC-associated illness and in those without an identifiable agent. While rotavirus was implicated in 3% of cases overall, when vomiting or vomiting plus dehydration occurred, rotavirus was identified with a rate of 10% and 12%, respectively. Dysentery was common only in Shigella cases, occurring in 24%. A decrease in occurrence of rotavirus, Campylobacter and possibly EPEC illness was seen in the infants less than 6 months of age who were breast-fed when compared to those who were not.

Visualization of coronary artery fistula with transesophageal echocardiography.

Coronary artery fistulas are relatively uncommon and are usually initially suspected on auscultation of a continuous murmur. Long-term complications include congestive heart failure, endocarditis, ischemia, and atrial arrhythmias. The role of echocardiography in visualization and diagnosis of these fistulas is expanding. We report two cases in which transesophageal echocardiography was used to visualize and better define proximal coronary arteries and coronary artery fistulas.

Isolation of a flavivirus related to the tick-borne encephalitis complex from human cases in Saudi Arabia.

A flavivirus related to the tick-borne encephalitis complex was isolated from the blood of 6 male butchers, aged 24-39 years, in Jeddah, Saudi Arabia in November and December 1995. Two of the patients died and the other 4 recovered completely. Four more patients, 3 males and 1 female, were diagnosed serologically by immunoglobulin M capture enzyme-linked immunosorbent assay and seroconversion in acute and convalescent blood samples examined by indirect immunofluorescent test using Vero cells infected with the isolated virus. The virus identity was confirmed at the Centers for Disease Control and Prevention, Fort Collins, Colorado, USA, by the polymerase chain reaction; it was closely related to Kayasanur Forest disease virus. All infected patients had similar clinical and laboratory symptoms and signs, including fever, headache, generalized body aches, arthralgia, anorexia, vomiting, leucopenia, thrombocytopenia, elevated liver enzymes (serum glutamic oxalacetic and serum glutamic pyruvic transaminases), elevated creatinine phosphokinase, and elevated blood urea. One patient developed symptoms of encephalitis, but survived without any sequel. Skin rash developed in 2 patients, morbilliform on the hands, feet, and lower abdomen of one patient and purpuric associated with melaena in the second patient. Eight of the 10 confirmed patients were working with sheep, and the disease may be a zoonotic viral infection.

The activity of serum ribonuclease in protein-energy malnutrition.

Serum alkaline ribonuclease activity and serum albumin concentration were determined in 25 normal children and 59 children with protein-energy malnutrition. The increase in serum ribonuclease was marked in marasmus and marasmic kwashiorkor. The ribonuclease activity dropped significantly after two weeks of treatment and returned to normal by four weeks. In kwashiorkor, serum ribonuclease activity was significantly lower than control and returned to normal after four weeks of treatment. These findings support previous observations that the serum ribonuclease is a good criterion of the nutritional status and indicates that the enzyme activity, particularly when related to serum albumin, is a good prognostic index in this respect.

Spontaneous regression of patient omphalomesenteric duct: from a fistula to Meckel's diverticulum.

A newborn with a patent omphalomesenteric duct is described in this report. This anomaly is a very rare one. Regression of the omphalomesenteric duct occurs as a normal embryonic event in the intrauterine life between the fifth and ninth week of gestation; however, in this case regression occurred spontaneously in the neonatal period and resulted in a Meckel's diverticulum with no connection with the umbilicus. This is the first case to be reported.

Penile dorsal angulation in a child without epispadias.

This is a report on a 5-year-old boy with dorsal penile angulation without epispadias. The surgical correction is described.

Acute appendicitis in children: when does ultrasound help?

Fifty-six patients with possible appendicitis were evaluated clinically and by ultrasound. Ultrasound examination visualized the appendix in 18 of the patients evaluated and showed another pathology in six others. It was useful when the clinical picture was not clear (25 patients) as it showed an inflamed appendix in 10 patients. This was of particular value when there was another critical illness making clinical evaluation difficult (three patients), and for the diagnosis of other unsuspected pathological conditions (six patients). It did not affect the line of management when the clinical picture was clear enough to diagnose or exclude acute appendicitis.

Detection of enteropathogens in fatal and potentially fatal diarrhea in Cairo, Egypt.

A 1-year study of the etiology of acute diarrhea complicated by severe (10%) dehydration, active bleeding, shock and cardiovascular collapse, pneumonia, acute renal failure, or seizures in infants under 18 months of age was performed in Cairo, Egypt. Of 145 infants, 19 (13%) died or left the hospital moribund; the remaining 126 patients were classified as having potentially fatal illness. A variety of enteropathogens were identified with approximately equal frequency in the fatal and nonfatal complicated cases as well as in 135 controls with severe uncomplicated diarrhea. The agents most frequently detected in infants with severe diarrhea in this population which were felt to be etiologically important were rotavirus (33%), heat-stable enterotoxin-producing Escherichia coli (20%), heat-labile enterotoxin-producing E. coli (11%), enteropathogenic E. coli (8%), and Salmonella spp. (5%). The high rate of occurrence of Giardia lamblia (35%) probably represented the high carriage rate of the protozoan in this population. Complicated (fatal and potentially fatal) cases differed from control cases in a number of ways: the onset of diarrhea was more sudden, the course was progressive and of greater initial intensity, vomiting occurred more frequently, the patients more often had visited another physician before coming to the hospital, the patients more often had respiratory symptoms and pulmonary abnormalities on auscultation, hypoactive bowel sounds and abdominal distention were more common, as was oliguria, and the patients showed lower mean body weights.

Cultivation and subgroup determination of human rotaviruses from Egyptian infants and young children.

Primary African green monkey kidney cells were more sensitive than primary cynomolgus monkey kidney and MA104 cells for supporting the growth of human rotaviruses detected in diarrheal stools of Egyptian infants and young children. In attempts to characterize these Egyptian rotaviruses, only 31% of the strains tested in the form of fecal suspensions were identified as subgroup 1 or 2. After one passage in African green monkey kidney cells, 80% of the strains were identified as subgroup 1 or 2. Of these 43 rotaviruses for which the subgroup was determined, 28% were subgroup 1 and 72% were subgroup 2. Thus, cultivation in African green monkey kidney cell cultures facilitated the antigenic characterization of rotaviruses by subgrouping; cultivation also represents an initial step in determining serotype and in developing potential vaccine candidates.

Illness and reservoirs associated with Giardia lamblia infection in rural Egypt: the case against treatment in developing world environments of high endemicity.

A longitudinal investigation of the health effects and reservoirs of Giardia was undertaken during 1984-1985 in 40 households located in the rural Nile Delta region of Egypt. Stool specimens obtained once weekly for six months from 2-4-year-old children were cyst- or trophozoite-positive in 42% of the 724 examined. Only one child remained Giardia-negative during the study. The mean duration of excretion in Giardia-positive children was seven and one-half weeks with a range of one to 17 weeks. Mucus was present in 52% of all stools collected, and fecal leukocytes were observed with surprising frequency in the absence of identifiable pathogens. Clinical symptoms of illness were frequently observed within a month before or after Giardia excretion in stool of children, but a statistical inference of association was not demonstrated. Seventeen per cent of 697 specimens obtained from their mothers were Giardia-positive for a mean duration of four weeks and a range of one to 18 weeks. A total of 962 specimens were collected from 13 species of household livestock. Giardia was detected in 22 specimens from cows, goats, sheep, and one duck. Giardia cysts were detected in three of 899 samples of household drinking water. The ubiquity of the protozoan as well as the failure to show an association between infection and symptomatic illness argue against the administration of Giardia-specific drugs to children in settings where the risk of reinfection is high and for whom intestinal insults are both varied and constant.