Congenital tracheobronchial stenosis in monozygotic twins

A pair of monozygotic twins suffering from noisy respirations and recurrent wheezes since early infancy were referred for evaluation. Using direct coronal CT and 3-dimensional reconstruction of the airway, congenital tracheobronchial stenosis was found in both twin babies, later confirmed by fibre optic bronchoscopy. The cause of congenital tracheobronchial stenosis remains obscure, but even in monozygotic twins an unidentified environmental factor cannot be excluded and may be responsible for discordant bronchopulmonary abnormalities.

CONCLUSION

This case report shows that tracheobronchial stenosis may present in monozygotic twins. The pattern of malformation in twins differs from cases described previously.

Activating a zymogen without proteolytic processing: mutation of Lys15 and Asn194 activates trypsinogen

The zymogen and mature enzyme forms of trypsin-like serine proteases exhibit a wide range of activities. The prototypical trypsinogen-trypsin system is an example of a minimally active zymogen and a maximally active mature protease. The present work identifies several features of trypsinogen which govern its activity. Our results indicate that rat trypsin is 10(8)-fold more active than rat trypsinogen. Rat trypsinogen appears to be less active than bovine trypsinogen. His40 is believed to be an important determinant of zymogen activity. We are unable to verify this role for His40 in trypsinogen since the mutation of His40 to Phe appears to change the trypsin-substrate interface. Deletion of the N-terminal Ile16 from trypsin is expected to produce a trypsinogen-like protein since the Ile16-Asp194 salt bridge cannot form. Such mutants have higher activity and BPTI affinity than trypsinogen, which indicates that the activation peptide stabilizes the inactive trypsinogen conformation. The mutation of Lys15 to Ala increases the BPTI affinity and activity of trypsinogen to an even greater extent; thus, removal of Lys15 can account for the effect of the loss of the activation peptide. These results suggest that Lys15 is an important determinant of zymogen activity. The mutation of Asp194 to Asn also increases the BPTI affinity and activity of trypsinogen. This result suggests that in addition to stabilizing the active conformation of trypsin via the Ile16-Asp194 salt bridge, Asp194 also maintains the inactive conformation of trypsinogen. A correlation exists between the values of kcat/Km and BPTI affinity of mutant trypsinogens and trypsins. However, the slope of this correlation is 0.64, which indicates that different "active" conformations are involved in BPTI binding and substrate hydrolysis. DeltaI16V17 trypsinogen is the lone outlier; its BPTI affinity is higher than would be expected based on the value of kcat/Km. We show that the rate of BPTI association is slower for DeltaI16V17 trypsinogen than for a mutant trypsinogen with a similar BPTI affinity. This observation suggests that BPTI binds to an "active" trypsinogen conformation that is not kinetically accessible to substrates.

Outbreak of Candida albicans fungaemia in a neonatal intensive care unit

During a 4-month period, 9 premature infants hospitalized in a neonatal intensive care unit (NICU) developed Candida albicans fungaemia. All 9 infants received antifungal agents. Fluconazole was administered in 7 patients and successfully eradicated this organism in 6 with no adverse effects. For epidemiological investigation, 64 environmental specimens and hand-washings of all 54 staff members involved in the NICU were examined for the presence of this organism. No C. albicans could be identified from environmental sources, while the hand-washing of 1 nurse was C. albicans-positive. Two genotyping methods, including electrophoretic karyotyping using contour-clamped homogeneous electric field gel electrophoresis and polymerase chain reaction-based direct sequencing of rRNA gene, were used in the analysis of the isolates recovered from blood cultures of the infants, the hand-washing of the nurse and 7 control isolates. Both methods yielded comparable results and revealed that all 13 isolates from infected infants as well as the isolate from hand washing of the nurse were of the same genotype while the control isolates were distinct. These results suggest that the outbreak of C. albicans fungaemia was caused by a particular strain and possibly via cross-infection. In addition, we showed that fluconazole seemed to be safe and effective in treating C. albicans fungaemia in neonates, although the data were limited.

Association of fungal colonization and invasive disease in very low birth weight infants

BACKGROUND

Fungi are common pathogens of nosocomial infections in the very low birth weight (VLBW) infants. The purpose of this study was to investigate the fungal colonization rate in VLBW infants and the association between fungal colonization and systemic fungal diseases.

MATERIALS

Between January 1, 1996, and December 31, 1996, 116 infants with birth weight < 1500 g admitted to the neonatal intensive care unit of Chang Gung Children's Hospital in the first day of life were included in this prospective study.

METHODS

Cultures from oropharynx, rectum, skin (groin and axilla), bag urine and endotracheal aspirates were obtained in the first 24 h after birth and weekly thereafter throughout their neonatal intensive care unit stay. Medical records were reviewed weekly.

RESULTS

Fungal colonization was detected in 25 infants, among whom 17 infants developed colonization by 2 weeks of life. Candida albicans (61%) and Candida parapsilosis (29%) were the 2 most common organisms. The rectum (76%) was the most frequent site of colonization. Factors significantly associated with colonization were prolonged administration of antibiotic therapy, parenteral nutrition and intralipid emulsion. Three of 116 infants developed fungemia. The association between colonization and subsequent fungemia was demonstrated in 1 infant, representing 4% of colonized infants.

CONCLUSION

Fungal colonization was detected in one-fifth of VLBW infants and represents a risk factor for fungemia. Because disease occurred in the absence of apparent colonization, factors other than colonization may contribute to invasive candidiasis.

Antimicrobial susceptibilities of Campylobacter jejuni and coli by using E-test in Taiwan

To report the in vitro antibiotic susceptibility of Campylobacter species, we determined the MICs of 6 antibiotics by E-test for 93 human clinical strains and 35 chicken strains. The 6 antimicrobial agents tested were gentamicin, erythromycin, clindamycin, tetracycline, ciprofloxacin, and nalidixic acid. Isolates from humans were significantly more susceptible than chicken strains to erythromycin, clindamycin and ciprofloxacin. Nearly all of the human and chicken strains were susceptible to gentamicin. Among human isolates of C. jejuni, cross-resistance between nalidixic acid and ciprofloxacin was found in 66% of the strains, but none of the nalidixic acid-susceptible strains was resistant to ciprofloxacin. The higher prevalence of ciprofloxacin resistance in this area may be attributable to the large amount use of quinolones in poultry. Because of the high resistance rates of chicken isolates to the commonly used antimicrobial agents, it is necessary to create innovative methods to limit the inappropriate use of antibiotics in poultry in order to prevent the spread of the drug-resistant strains to humans.

Characterization and functional analysis of the porcine lactoferrin gene promoter

Lactoferrin, a ferric binding glycoprotein found in milk, can possibly prevent microbial infection of the mammary gland and gastrointestinal tract. To define the regulation of the porcine lactoferrin gene (pLTF), we cloned its 5'-flanking region from a porcine liver genomic library and analyzed the 5' upstream region of approx. 4kb, two exons, and an intron. The transcription start site was localized by primer extension to residue G, which is 41 nucleotides upstream from the ATG start codon. The pLTF 5'-flanking region possesses several putative cis-acting regulatory elements found in both housekeeping and inducible genes; to define their function, they were inserted into a chloramphenicol acetyltransferase reporter construct. The region up to -156 sufficed for basic promoter activity, whereas the region up to -780 was required for maximal promoter activity in porcine testis cells (STcells), kidney cells (PK15 cells) and human mammary epithelial cells (HBL-100 cells). Detailed analysis of this proximal region by DNase I footprinting and electrophoretic mobility shift assays reveals that the ubiquitous factors SP1, AP2 and the mammary gland-specific factor (MGF) might play significant roles in regulating the transcription of the pLTF gene.

Spontaneous resolution of an intratracheal mass: report of one case

A 14 year-old boy was investigated for a slowly resolving right upper lobe consolidation persisting for 3 months after a pneumonic episode. A flexible bronchoscopy showed a polypoid mass in the carina with extension to the right proximal bronchus. The bronchial washings study for fungus, acid-fast bacilli and polymerase chain reaction for mycobacterium were negative. A reported bronchoscopic examination 8 months later revealed no tracheal mass or subsequent stenosis. A tracheal mass in an asymptomatic and non-progressive child may be managed alternatively by repeated bronchoscopic examinations at intervals instead of immediate bronchoscopic excision or thoracotomy.

Swyer James syndrome following Mycoplasma pneumoniae pneumonia: report of one case

A previous healthy 5 year-old girl developed a right hyperlucent lung following Mycoplasma pneumoniae pneumonia 14 months before admission. Serial chest radiographs revealed a persistent right upper lobe atelectasis and gradual development of the right hyperlucent lung associated with frequent bouts of wheezing and exertional dyspnea. Physical examination showed markedly decreased breathing sounds in the right hemithorax with fine inspiratory crackles and expiratory wheezes. A diagnosis of Swyer James syndrome was confirmed by the exclusion of other causes of unilateral hyperlucent lung using computed tomographic scans of chest, fiberoptic bronchoscopy and lung perfusion scintigraphy. She has been followed up at our hospital using anti-asthmatic medication.

Schizophrenia: conceptual change in modern psychiatry

Schizophrenia is perhaps the most devastating mental illness that psychiatrists must treat. Its chronic course with deteriorating consequences has been the focus of study throughout this century. This paper reviews the concept of schizophrenia, from fundamental Kraepelinian theory of 'dementia praecox' to biological correlates and explanation. Its causes, however, remain obscure and there were no appreciable changes in its treatment modality. A 'bio-psycho-social' model of care is emphasized, aiming at the prevention of deterioration of symptoms, functional impairment, disability and social handicap.

Hair growth cycle affects hair follicle destruction by ruby laser pulses

It has been shown that normal mode ruby laser pulses (694 nm) are effective in selectively destroying brown or black pigmented hair follicles in adult Caucasians. This study investigated how the various stages of the hair follicle growth cycle influence follicle destruction by ruby laser treatment, using a model of predictable synchronous hair growth cycles in the infantile and adolescent mice. A range of ruby laser pulse fluences was delivered during different stages of the hair growth cycle, followed by histologic and gross observations of the injury and regrowth of hair. Actively growing and pigmented anagen stage hair follicles were sensitive to hair removal by normal mode ruby laser exposure, whereas catagen and telogen stage hair follicles were resistant to laser irradiation. Selective thermal injury to follicles was observed histologically, and hair regrowth was fluence dependent. In animals exposed during anagen, intermediate fluences induced nonscarring alopecia, whereas high fluences induced scarring alopecia. The findings of this study suggest treatment strategies for optimal laser hair removal.

Downregulation and subcellular redistribution of the gamma-aminobutyric acidA receptor induced by tunicamycin in cultured brain neurons

The significance of N-linked glycosylation and oligosaccharide processing was examined for the expression of gamma-aminobutyric acidA receptor (GABA(A)R) in cultured neurons derived from chick embryo brains. Incubation of cultures with 5 microg/ml of tunicamycin for 24 h blocked the binding of 3H-flunitrazepam and 3H-muscimol, probes for the benzodiazepine and GABA sites on the receptor, by about 20% and 28%, respectively. The loss of ligand binding was due to a reduction in the number of binding sites with no significant changes in receptor affinity. Light microscopic immunocytochemistry also revealed that the treatment reduced approximately 13% of the intensity of GABA(A)R immunoreactivity in the neuronal somata. Furthermore, the fraction of intracellular receptors was decreased to 24% from 34% of control in the presence of the agent, as revealed by trypsinization of cells in situ followed by 3H-flunitrazepam binding. The molecular weight of the receptor subunit protein was lowered around 0.5 kDa after tunicamycin treatment, in accordance with that following N-glycosidase F digestion, indicating the blockade of N-linked glycosylation of GABA(A)R by tunicamycin. Moreover, intense inhibitions of 91% and 44%, respectively, were detected to the general galactosylation and mannosylation in the tunicamycin-treated cells, whereas the protein synthesis was hindered by 13%, through assaying the incorporation of 3H-sugars and 3H-leucine. Nevertheless, treatment with castanospermine or swainsonine (10 microg/ml, 24 h), inhibitors to maturation of oligosaccharides, failed to produce significant changes in the ligand binding. In addition, in situ hybridization analysis showed that these three inhibitors did not perturb the mRNA of GABA(A)Ralpha1-subunit. The data suggest that tunicamycin causes the downregulation and subcellular redistribution of GABA(A)R by producing irregularly glycosylated receptors and modifying their localization. Both galactosylation and mannosylation during the process of N-linked glycosylation may be important for the functional expression and intracellular transport of GABA(A)R.

Yeast carriage on hands of hospital personnel working in intensive care units

The frequency and distribution of yeast carriage on the hands of hospital personnel working in intensive care unit (ICUs), was investigated. Hand carriage of yeast and Candida species was 46 and 29%, respectively. Rhodotorula sp. and Candida parapsilosis were most frequently recovered. There was no significant difference in frequency or distribution of yeasts and Candida sp. recovered among the three ICUs. Seventeen C. parapsilosis isolates and three Candida albicans isolates were genotyped by electrophoretic karyotyping using contour-clamped homogenous electric-field gel electrophoresis. Eleven separate types of C. parapsilosis and two types of C. albicans were identified. There was no common genotype among these isolates, even within the same unit. We conclude that yeast carriage on the hands of personnel working in ICU is common, but these yeasts are usually not acquired from a common source in the ICU.

Hypothermia predisposing to Pseudomonas putida sepsis in a child with panhypopituitarism

A 14-year-old boy presented with a 1-week history of hypothermia and obtundation. His medical history included surgical resection of craniopharyngioma with postoperative visual impairment and panhypopituitarism. The patient's rectal temperature remained persistently lower than 35 degrees C during the first 3 days of hospitalization. His blood pressure was 90/56 mmHg on admission. The peripheral blood leukocyte count was 2.7 x 10(10)/L with 18% neutrophils, 19% band forms, 44% metamyelocytes, 3% myelocytes, and 16% lymphocytes. The C-reactive protein concentration was 133.9 mg/L. Two separate blood cultures both yielded Pseudomonas putida. The patient was treated with amikacin and ceftazidime along with aggressive fluid therapy. Replacement therapy directed at his hormonal deficiencies was initiated as soon as his hemodynamic status was stabilized. The patient responded well to therapy with a gradual rise in body temperature and improvement in general activity. A growth experiment carried out on the P. putida isolate showed that the bacteria grew more rapidly at 30 degrees C than at 37 degrees C. The clinical course of the patient, as well as the results of the laboratory study, suggest that hypothermia may predispose human infection with P. putida.

Hemoptysis in children

BACKGROUND

Hemoptysis is rare in children, yet is one of the most frightening manifestations of cardiopulmonary disease. A wide spectrum of diseases has been reported to cause hemoptysis in children, but the search for a specific cause can be tedious and unrewarding. Early diagnosis and interventions of hemoptysis are extremely important for the successful management of this potentially lethal process in children.

METHODS

From July 1994 to June 1996, 15 pediatric patients ranging from 1 month to 15 years of age were admitted to the Pulmonology division for the investigation of hemoptysis. We retrospectively reviewed the clinical records and diagnostic evaluations of these patients.

RESULTS

Six (40%) of the patients investigated were infectious in origin, only one patient had tuberculous infection. Three patients had a traumatic cause and 2 patients had foreign bodies in the airway. Two cases had no obvious contributing cause of hemoptysis despite extensive investigations. One patient had hematemesis because bleeding from esophageal ulcerations was misinterpreted as hemoptysis. One patient had varicosed tracheal and bronchial collaterals causing massive hemoptysis due to portal vein obstruction and hypertension.

CONCLUSION

Pulmonary infection was the leading cause of hemoptysis in the 15 children we studied, but Mycobacterium tuberculosis is an uncommon causative agent. Bronchoscopy is an extremely useful tool for the diagnosis and localization of hemoptysis. Hematemesis may be misinterpreted as hemoptysis, particularly when an accurate history is not possible in children, therefore, bleeding from the upper aerodigestive tract should be studied meticulously and excluded adequately using endoscopy.

Pneumonia with pneumatocele formation caused by Mycobacterium tuberculosis: report of one case

Pneumatoceles are usually characteristic of staphylococcal pneumonia. They are rarely formed as one of the complications of Mycobacterium tuberculosis pneumonia. We report a 1-year-and-5-month old male child with pneumonia who was confirmed to have the rare complication, pneumatocele formation, by chest radiography and computed tomography. Since the patient did not respond to empiric antibiotic therapy, gastric larvage through a nasogastric tube was performed on three consecutive mornings and, as a result, acid fast rods were found on the three specimens. The cultures subsequently yielded M. tuberculosis. He was finally cured with a 6-month course of antituberculous chemotherapy. We conclude that tuberculosis should be considered in infants or young children with pneumonia that presents radiologically as pneumatocele formation, especially in whom there has been no response to empiric antibiotic therapy.

Oral acyclovir prophylaxis of varicella after intimate contact

OBJECTIVES

Whether oral acyclovir (ACV) given in late incubation can prevent clinical varicella or not.

MATERIALS AND METHODS

Twenty-seven healthy infants and children susceptible to varicella received oral ACV (40 mg/kg daily in four divided doses) for 5 days, starting 9 or 11 days after exposure from the index case in the family (2 in the classroom). The clinical features were compared with 13 control children who did not receive ACV. Enzyme-linked immunoassay was used to detect varicella-zoster virus (VZV) antibody and, in follow-up immunologic studies, lymphocyte proliferative response was added. In some cases, blood culture and polymerase chain reaction with Southern hybridization were used for detection of viremia.

RESULTS

Among the 27 children in the treatment group, two (7.4%) developed the disease and seroconversion was observed in 17 subjects (63%). Follow-up immunologic studies in 12 of these 17 seroconverted subjects 30 months later showed persistent cellular and/or humoral immunity to VZV. Only one subject, bled 11 days after exposure, had positive VZV DNA and blood culture for VZV. On the other hand 10 of 13 (77%) control subjects developed clinical varicella.

CONCLUSIONS

Oral ACV administration to healthy susceptible subjects at the beginning of secondary viremia in the late incubation period (9 days after exposure) can effectively prevent or modify clinical varicella.

Specific immune response in adult medical personnel immunized with acellular pertussis vaccine with special emphasis on T helper cell response

Recent epidemiologic data have indicated that adults are the most important reservoir that transmit pertussis to children. However, conventional whole cell pertussis vaccine is contraindicated in adults and children over 7 years of age because of the unacceptably high rate of adverse reactions. The aim of this study is to evaluate the specific cellular immune responses and adverse reactions to a less reactogenic acellular pertussis vaccine in adult volunteers. Eighty healthy medical personnel in Chang Gung Children's Hospital were enrolled. Volunteers in each group received: (1) Td + full strength acellular pertussis vaccine (PT, 1 microgram/0.5 ml; FHA, 4 micrograms/0.5 ml); (2) Td + half strength acellular pertussis vaccine; (3) Td alone. Lymphocyte phenotypic analysis, antigen-specific antibody titers, antigen-specific proliferative response and cytokine levels were evaluated before and 1 month after vaccination. Our data revealed: (1) the adverse reactions were minimal; (2) phenotypic analysis showed no non-specific activation of helper T or memory T cell after vaccination; (3) both PT and FHA-specific antibody titers increased significantly after vaccination, (4) PT antigens had a mitogenic effect on cord blood mononuclear cells and peripheral blood mononuclear cells of the adult volunteers; (5) FHA-specific T cell proliferative responses significantly increased after vaccination; (6) the cytokine production pattern showed predominant activation of Th 1 cells as reflected in increased production of gamma-IFN after vaccination. Acellular pertussis vaccine can effectively induce both humoral and cellular immune response in adults.

Acetaminophen overdose in children and adolescents

From 1982 to 1997, 12 Chinese children were admitted to Chang Gung Memorial Hospital with acetaminophen overdose. Six subjects (one young child, and five adolescents) developed liver damage which was severe in three cases (AST > 1000 IU/L). Acetaminophen-induced liver function abnormalities were characterized by elevation of transaminase levels with ALT higher than AST(6/6), coagulopathy(5/6), thrombocytopenia (1/6), but absence of jaundice(6/6). Fortunately, none of the six patients with liver damage developed fulminant liver failure, and all recovered completely. Acetaminophen overdose can cause significant morbidity in children and adolescents. Caretakers should be well instructed to give the drug correctly. So far, acetaminophen is still considered as the drug-of-choice for antipyresis in pediatric practice. However, multicentered collaborative study is necessary to determine whether acetaminophen intoxication causes less hepatic failure in Chinese children than in Western children.

Isolation and expression of a porcine lactoferrin gene

OBJECTIVE

To elucidate the spatial and temporal expression of a porcine lactoferrin (LTF) gene.

ANIMALS

4 female and 4 male Large White pigs.

PROCEDURES

We examined LTF expression in various organs excised from the pigs, using northern blot hybridization with a porcine LTF cDNA probe. Antibodies against porcine LTF were raised in rabbits and were used along with immunohistochemical staining to localize the LTF protein.

RESULTS

High amounts of porcine LTF mRNA were detected in the secreting mammary gland and epididymis. This distribution is consistent with that of porcine LTF examined by immunohistochemistry. In female pigs, porcine LTF mRNA concentration increased remarkably in the ductal cells of the lactating mammary gland then significantly decreased at day 21 after parturition. Furthermore, specific staining for LTF was observed in the epithelial cells of the gastrointestinal tract of female pigs, but not in the uterus, ovaries, spleen, kidneys, pancreas, muscles, heart, brain, lungs, or liver of postpartum female pigs, or in the testes of male pigs.

CONCLUSIONS

Gene expression of porcine LTF is closely related to lactation in the mammary gland. Distribution of LTF in the epididymis suggests that LTF may have a regulatory role in development of the reproductive tract of male pigs.

Fatal Haemophilus influenzae pneumonia: two cases report

Haemophilus influenzae is a common cause of acute childhood pneumonia. Most Haemophilus pneumonia generally follow a benign course with occasional complications of pleural effusion, pneumothorax or pneumatocele. Deaths following invasive Haemophilus pneumonia have rarely been reported in children older than 3 years of age. We report 2 deaths in children presenting with fulminant pneumonia, complicated by sepsis and adult respiratory distress syndrome despite vigorous antibiotic therapy and full resuscitative measures.

Salmonella typhimurium brain abscess in a six-month-old infant: a case report and review of the literature

We report the case of a six-month-old male infant with brain abscess caused by Salmonella typhimurium. Upon admission, he was suffering from fever, diarrhea, drowsiness and convulsion. Salmonella meningitis was identified by CSF examination. Following failure of antibiotic therapy to control his fever, brain computerized tomography (CT) was ordered 5 days later and revealed a brain abscess. He received surgical excision of the abscess and recovered completely after receiving ceftriaxone therapy for 8 weeks. The case of our patient, together with 11 cases of Salmonella brain abscess from the English literature are reviewed. There was a male preponderance among these patients (male: female = 2.67 : 1) and the majority were less than one year old. Salmonella typhimurium, typhi, and enteritidis occurred most frequently. Fever, seizure, signs and symptoms of increased intracranial pressure and change in mental status were the most common clinical features. Purulent meningitis was a major predisposing factor. Successful treatment was associated with early identification, prompt surgical intervention, high dose, long-term antibiotic therapy, and close follow-up for possible recurrence and to determine the presence of neurological sequelae.

Hepatitis C and G virus infections in polytransfused children

The prevalence of hepatitis C virus (HCV) and a newly identified hepatitis G virus (HGV) and their clinical significance were studied in 42 polytransfused Taiwanese children. Serological assays for antibodies against HCV (anti-HCV) and polymerase chain reaction for serum HCV ribonucleic acid (RNA) and HGV RNA were performed. The prevalence of anti-HCV and HGV RNA was 17% and 14%, respectively in 42 polytransfused children. Anti-HCV seropositives had a significantly higher mean age, peak serum transaminase level, and longer transfusion duration than seronegatives, while children with HGV infection usually had no or only mild hepatitis activities. The prevalence of anti-HCV dropped sharply after implementation of anti-HCV screening, however the prevalence of HGV viraemia remained unchanged.

CONCLUSIONS

HGV infection is not uncommon in polytransfused Taiwanese children and the virus does not cause significant hepatitis compared to HCV infection. Current blood donor screening for anti-HCV can effectively protect polytransfused children from HCV infection but the impact of additional screening for HGV markers awaits further studies.