In silico analysis of Naegleria fowleri cathepsin B paralogs: important drug targets.

Naegleria fowleri is a deadly human pathogen that causes primary amoebic meningoencephalitis (PAM). In this study, in silico investigations of two important N. fowleri cathepsin B paralogs, i.e., copies of genes resulting from a gene duplication event, were carried out using comparative modeling and molecular dynamics (MD) simulations. Comparative models of both paralogs showed significant architectural similarity with their template, i.e., rat cathepsin B. However, in N. fowleri cathepsin B (UniProt ID: X5D761) and putative cathepsin B (UniProt ID: M1HE19) enzymes, eleven and fifteen residues in the occluding loop regions were deleted, respectively, suggesting that these enzymes have a short occluding loop. Thus, it is concluded that N. fowleri cathepsin B and putative cathepsin B enzymes lack exopeptidase activity but possess enhanced endopeptidase activity and an affinity for macromolecular inhibitors. MD simulations further confirmed that prosegments (macromolecular inhibitors) bond more tightly with both enzymes than with wild-type cathepsin B. Additionally, a mutation was identified at an important N-glycosylation site; this mutation is believed to affect cathepsin B targeting inside the cell and make cathepsin B available in the extracellular environment. Due to this important N-glycosylation site mutation, these enzymes are secreted in the extracellular environment via an alternative, still unknown, posttranslational processing strategy. The present study is the first to predict the three-dimensional folds of N. fowleri cathepsin B paralogous enzymes, including a detailed description of the active site architecture and information about propeptide binding mode. This information can contribute to the discovery of novel and selective treatments that are effective against N. fowleri.

Allelic variations in CYP2D6 gene and susceptibility to cervical cancer.

Epidemiological studies have identified a number of risk factors that contribute to the development of cervical cancer precursors and cervical cancer. These include infection with certain oncogenic types of human papillomaviruses (HPVs) and other socio-economic factors. Tobacco smoking is an independent risk-factor for cervical neoplasia. It has been found that polymorphism at loci that encode carcinogen-metabolizing enzyme such as cytochrome P450 2D6 (CYP2D6) catalyzing the detoxification of carcinogens may determine susceptibility to cervical cancer. Therefore, it is likely that an understanding of these allelic differences is important for determining an individual's risk of cancer and susceptibility to potentially toxic agents. The aim of the present study was to elucidate the role of CYP2D6 polymorphism and susceptibility to squamous cell carcinoma of the uterine cervix in Indian population. Therefore, the genotype frequencies at this locus in females suffering with low-grade CIN, high-grade CIN and squamous cell carcinoma were compared. The control group consisted of 77 females with normal cervical cytology and the cases comprised of 61 mild/moderate dysplasia, 48 severe dysplasia and 45 cases of squamous cell carcinoma of uterine cervix. The individuals were divided into poor metabolizers (PM) and extensive metabolizers (EM) on the basis of their ability to metabolize certain drugs and carcinogens. Comparison of the frequency distribution for the combination of CYP2D6 EM genotype and smoking between mild/moderate and severe dysplasia was statistically significant (p=0.047) suggesting that women with cervical intraepithelial neoplasia I/II (CIN I/ CIN II) and CYP2D6 EM genotype who smoke appears to have more chances for the lesions to progress to CIN III. Whereas, frequency distribution for the same combination between severe dysplasia and squamous cell carcinoma failed to attain any statistical significance suggesting that CIN III with CYP2D6 EM genotype has less chance to progress to cervical cancer. Increased frequency of CYP2D6 EM and tobacco smoking show strong association with CIN III, indicating that not all lesions with the histopathological high grade CIN are premalignant. Conversely some squamous cell carcinomas may not be preceded by CIN.

Fulminating subacute sclerosing panencephalitis: case report and literature review.

We describe a young urban boy with atypically fulminant subacute sclerosing panencephalitis (SSPE). He had measles at 3 years of age despite receiving measles immunization in infancy. The literature describing acute SSPE is reviewed and summarized. This report reiterates the need to include SSPE as a diagnostic possibility in acute encephalopathic processes. The dismal prognosis of SSPE further emphasizes the need for measles vaccination and revaccination of all children who are initially immunized at an age of less than 15 months.

Combined effects of cadmium and linear alkyl benzene sulfonate on Lemna minor L.

: The effects of 0.1 ppm cadmium and 0.005% linear alkyl benzene sulfonates (LAS) on the uptake and metabolic incorporation of (14)C glycine by Lemna minor L., after 2, 24 and 48 h were studied for antagonistic/synergistic effects. Combined exposure was found to decrease the (14)C incorporation into proteins, DNA, RNA and phospholipids, to a greater extent than individual exposure. The presence of LAS increased the uptake of (109)Cd in the plants.

Presentation of Yersinia enterocolitica enteritis in children.

Yersinia enterocolitica enteritis is a potentially treatable infection. To understand its seasonal incidence and clinical presentation in children, we reviewed case records of children seen in Cardinal Glennon Children's Hospital in St. Louis, MO. We found the incidence of Yersinia enteritis to be as frequent as enteritis caused by Campylobacter. It occurred more frequently during the winter months (P < 0.002) than during the rest of the year. Fever was common in infants with Yersinia enteritis. Abdominal pain and distention were infrequent. Seventeen (35%) patients were 3 months of age or younger; 4 of 17 (28%) developed Yersinia sepsis as a complication of the enteritis. Physicians should perform stool cultures for Y. enterocolitica in young infants who present with high fever and diarrhea in winter months, especially when there is blood in stools or the patient appears septic.

Ketoconazole treatment of a family with zoonotic sporotrichosis.

All 3 members of a family developed lymphocutaneous and cutaneous sporotrichosis after exposure to an infected cat. The lesions resembled acute bacterial lymphadenitis and lymphangitis and responded within 2 weeks to ketoconazole treatment with complete healing and no recurrence over the next 6 months. Immunologically normal children and adults with lymphocutaneous or cutaneous sporotrichosis may respond well to ketoconazole therapy.

Bioavailability and toxicity to rats of bound residues of 14C-pirimiphos-methyl in stored wheat.

Wheat grains were treated with 14C-pirimiphos-methyl to generate bound residues for testing their bioavailability to rats. Bound residues accounted for 25% of the applied dose (50 ppm) at the end of one year. When the grain bound residues were fed to rats for 48 hours the animals eliminated 30 and 40% of the administered dose in urine and feces respectively, after 5 days. Radioactivity in some selected organs and blood accounted for 37% of the administered dose after 2 days, which gradually declined to 1% after 5 days. These data indicate that wheat-bound pirimiphos-methyl residues are moderately bioavailable to rats. In a 90-day feeding study, inhibition of plasma cholinesterase and brain acetylcholinesterase strongly suggest that the bound residues possess a toxicological potential.

Therapy of multidrug resistant typhoid in 58 children.

Treatment of children with infections caused by Salmonella typhi strains resistant to the commonly used oral antimicrobials is a special problem. As children cannot be treated with quinolones, there is no form of oral therapy. Third generation cephalosporins, which have been shown to be effective against typhoid caused by ampicillin sensitive strains of S. typhi were effective against typhoid caused by ampicillin, chloramphenicol and sulfamethoxazole/trimethoprim-resistant strains. We treated 28 children with ceftriaxone and 8 with cefotaxime. We found ceftriaxone to be more effective than cefotaxime with significantly lower relapse rate. Antibiotic therapy of 19 other children, initially treated in a similar manner, was altered for ease of therapy or due to poor response to therapy. The high cost of this parenteral therapy and the problems in its delivery point to the need for safe, effective oral therapy.

Multidrug-resistant typhoid in children: presentation and clinical features.

Typhoid accounts for 8% of pediatric admissions to the Aga Khan University Hospital in Karachi, Pakistan. Over a 4-year period (1986-1989), 355 children had typhoid documented by culture of blood or bone marrow. Strains of Salmonella, resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole accounted for 20% of these cases. Compared with children infected by drug-susceptible strains of Salmonella, children with multiresistant infection were generally sicker at presentation and were more likely to be assessed as appearing "toxic" (P less than .001), as having disseminated intravascular coagulation (P less than .01), and as exhibiting hepatomegaly (P less than .01). The mortality was 4.2% among children with multiresistant infection and 1.4% among those infected with strains susceptible to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole; the higher mortality in the former group was probably due to a longer duration of illness (P less than .05) and to ineffectual oral antimicrobial therapy before hospitalization.

Neonatal sepsis in Pakistan. Presentation and pathogens.

The case records of all neonates admitted to the neonatal unit at Aga Khan University Hospital (Karachi) in a 30 month period (Nov. 86-April 89) were analysed. Of 60 neonates with confirmed sepsis, 33 (55%) had non-nosocomial infection (NNC) whereas 27 (45%) had nosocomial sepsis (NC). The most common organisms causing early-onset NNC sepsis were Klebsiella species (53%) and Escherichia coli (10%), whereas the organisms causing late-onset NNC sepsis included Salmonella parathypi (21%), Group A Streptococcus (21%), Escherichia coli (14%) and Pseudomonas species (14%). Klebsiella was the most common organism causing NC sepsis, others being Staphylococcus aureus (15%) and Serratia species (15%). The mortality in NC sepsis, early-onset and late onset NNC sepsis was 44%, 26% and 43%, respectively. Risk factors associated with NNC sepsis included low birthweight, prematurity and prolonged and complicated deliveries. There was a high incidence of drug resistance to ampicillin and gentamicin among gram-negative organisms causing sepsis (mean 67%).

Inhalation toxicity of methyl isocyanate: biochemical and cytological profile of bronchoalveolar lavage fluid in rats.

Acute pulmonary injury in rats following a single inhalation exposure to methyl isocyanate (3.2 mg l-1) was reflected by alterations in the biochemical and cytological constituents of bronchoalveolar lavage fluid (BALF) over a period of 30 days. Total protein, sialic acid and lactic acid contents of BALF were increased followed by a gradual decline to normalcy between day 3 and day 30 post-exposure. The activity of lactic dehydrogenase also increased progressively with time. The cellularity of BALF was increased significantly and primarily comprised of polymorphonuclear neutrophils at 8 days. The adherence of macrophages was unchanged but their viability was lowered at 30 days post-exposure. The results indicate the significance of bronchoalveolar lavage analysis in monitoring pulmonary toxicity by methyl isocyanate, which is characterized by the hypoxic condition and reduced cellular defence. Some toxic manifestations are potentially reversible with time after cessation of exposure.

Chloramphenicol therapy of typhoid fever.

In a prospective study we compared two different dosage regimens of IV chloramphenicol succinate (100 mg/kg/day and 75 mg/kg/day) in children with culture proven typhoid. Trough and peak blood samples, obtained at 48 hrs, were analysed for free chloramphenicol by high pressure liquid chromatography (HPLC). Although the mean trough (8.8 +/- 7.7 versus 5.4 +/- 2.6 mcg/ml) and peak (19.9 +/- 12.2 versus 15.4 +/- 6.1 mcg/ml) chloramphenicol concentrations were comparable in both groups, a significantly wider range was found in the group receiving 100 mg/kg/day. Potentially toxic levels (greater than 30 mcg/ml) developed in two patients with liver dysfunction. Chloramphenicol in a dosage of 75 mg/kg/day is adequate and safe for the treatment of paediatric typhoid.

Hepatic dysfunction in paediatric typhoidal salmonellosis.

Although hepatic dysfunction has been described among adults with typhoid, there are few reports of significant hepatic functional impairment in children with typhoid. Of 435 children with culture-proven typhoid seen at the Aga Khan University Hospital, hepatomegaly was noted in 125 (29%) and isolated right hypochondrial tenderness in three (7%). Liver function tests performed on 156 of these children were normal in 121 (78%) and showed significant hepatic dysfunction in 35 (22%). Patients with significant hepatic dysfunction were more toxic (p less than 0.001) at presentation and had higher mortality (p less than 0.002) than those with normal liver function. Two children presented with a picture of fulminant hepatic failure with fatal outcome.

Neonatal screening for congenital hypothyroidism in Pakistan.

Congenital hypothyroidism is a preventable cause of mental retardation. Since clinical signs of congenital hypothyroidism do not generally become obvious before three months of age, screening programmes have been introduced in North America and Europe, which consist of T4 or TSH screening on newborn infants on the third day of life. The screening for congenital hypothyroidism was initiated in Pakistan by the Aga Khan University Hospital (AKUH) in March 1987. By April 1988, 5000 neonates were screened and five cases of congenital hypothyroidism were diagnosed. The study revealed the incidence of hypothyroidism to be one case per 1000 newborns which is about 4 times more than that in the West.

Branhamella catarrhalis meningitis following otolaryngologic surgery.

A case of pyogenic meningitis caused by Branhamella catarrhalis which occurred after pharyngoplasty, adenoidectomy and tympanostomy tube placement is reported. This organism is morphologically similar to Neisseria meningitidis but often produces beta lactamase. Therefore therapy should be directed by proper microbiologic identification and sensitivity results.