Heterogeneity in the haemagglutinin gene and emergence of the highly pathogenic phenotype among recent H5N2 avian influenza viruses from Mexico.

Molecular changes in the haemagglutinin (HA)-coding regions and proteolytic cleavage sites from multiple H5N2 subtype viruses isolated during a recent outbreak of avian influenza (AI) in central Mexico have been characterized. Eighteen isolates, collected during a 15 month period (October 1993 to January 1995) from six central states, were sequenced. None of the 18 predicted HA1 amino acid sequences were identical and changes were not restricted to a specific region of the sequence. Phylogenetic analyses of the HA1 sequences demonstrated two virus lineages, designated Puebla and Jalisco, with sequence variation as high as 10.5 percent for amino acid and 6.2 percent for nucleotide sequences. During the latter months of the surveillance period, highly pathogenic (HP) strains of AI emerged causing lethal disease in commercial poultry flocks. In each of the HP strains isolated, the HA protein was cleaved in chicken embryo fibroblast cells in the absence of trypsin, and two alterations not found in earlier non-HP isolates were detected. In the HA protein, HP strains all had a glutamic acid --> lysine substitution at amino acid position 324 and an insertion of arginine and lysine as new residues 325 and 326. The insertion appears to be due to a duplication of the nucleotide sequence AAAGAA at nucleotide positions 965-970 of the HA1-coding region. Computer-assisted secondary structure analyses place the target for the insertion in a predicted RNA stem-loop structure. A mechanism is suggested by which the polymerase duplicates the sequence.

Dynamics of bioactive luteinizing hormone-human chorionic gonadotropin during the first 7 days of life.

Serum luteinizing hormone-human chorionic gonadotropin bioactivity (B-LH) was measured daily in seven male and four female full-term newborns during the first 7 days of life. The B-LH levels were elevated in both sexes during the 1st day of life; subsequently, values decreased in both sexes. In males, they reached a nadir on the 4th day of life. A gradual secondary rise was then observed with B-LH levels on the 7th day significantly higher than on day 4 (p less than 0.025). By contrast, the B-LH levels in the females continued a gradual decline to levels significantly lower on day 7 as compared to day 4 (p less than 0.05). To determine whether pulsatile B-LH secretion occurs in newborns, serum concentrations were measured every 20 min for 2 h in eight male and seven female full-term neonates on the 7th day of life. Pulsatile secretion of B-LH was detected in six males and six females. This study demonstrates that pulsatility of gonadotropin secretion is characteristic of neonates as early as 7 days of life and that there is a dichotomy between the levels of B-LH in males and females; levels in females decline progressively from day 1 through 7, whereas in males, a nadir is reached on day 4 with a secondary rise developing thereafter. This male sex-specific rise is presumably the drive responsible for the characteristic postnatal increase in testosterone which peaks at 1 to 2 months of age.

Sexual precocity in a male due to thoracic polyembryoma.

A 7-year-old boy with sexual precocity of recent onset was found to have elevated levels of chorionic gonadotropin, alpha fetoprotein, and testosterone. Removal of a retropleural, posterior mediastinal mass with an intraspinous epidural extension was followed by prompt declines in the plasma concentrations of the tumor markers and cessation of adolescent development. The neoplasm proved to be a polyembryoma, unusual in the multiplicity of its embryoid bodies and extra gonadal location. Following local irradiation and two years of systemic chemotherapy, the patient, now 13 years of age, has done well except for evidence of testicular tubular insufficiency.

Epidemiology of high-tension electrical injuries in children.

Twenty-seven acute high-tension electrical injuries were seen in seven years at the Shriners Burns Institute. All were in boys 7 to 16 years old; 13 suffered amputation(s) and 2 died. Most accidents occurred when boys climbed utility poles (9), trespassed, generally around transformer substations (9), or contacted power lines when tree climbing (5). All occurred in daylight, generally between 4 and 6 PM, on weekends in warm weather with boys in groups. Preventive education directed to this high-risk population should illustrate properties of high-voltage electricity, effects on the body, and how to cope with peer pressures in unstructured time.

Cushing syndrome, sexual precocity, and polyostotic fibrous dysplasia (Albright syndrome) in infancy.

The sexual precocity of polyostotic fibrous dysplasia is occasionally accompanied by other endocrine disorders, but in only two previous instances has Cushing syndrome been reported. The history of a 6-month-old girl is presented, in whom this syndrome was complicated by congenital Cushings syndrome. Although endocrinopathies of polyostotic fibrous dysplasia have usually been ascribed to a central (hypothalamic) origin, the findings in this patient suggest autonomous hyperfunction of the peripheral endocrine glands, with the Cushing syndrome caused by hyperplastic nodules in the adrenal glands and the precocity by luteinized follicular cysts of the ovary.