To clarify the preventive effects of glucocorticoid on perinatal hypoxic-ischemic (HI) brain damage, an experiment was carried out on 4-day-old rats pretreated for 4 consecutive days with 3 different regimens; namely, a low dose dexamethasone (Dex) (0.1 mg/kg/day), a high dose Dex (0.5mg/kg/day), and a saline administration. On the 7th postnatal day, after ligation of the left common carotid artery, the rats were exposed to 8% oxygen and decapitated on the 10th, 14th, 21st and 28th postnatal days. Ligated side brain damage was observed in 75, 7 and 3% of the rats in the saline, low and high dose Dex groups, respectively. However, a high mortality rate (42%) was noted in the high dose Dex group. The cumulative number of animals with poor outcome (death or brain damage) was 49 (80%), 13 (33%) and 24 (44%) in the saline, low and high dose Dex groups, respectively. On the 10th and 14th postnatal days, the rats in both the Dex groups showed delayed neuronal maturation and myelination in the non-ligated side motor cortex, however, these maturational differences disappeared on the 21st postnatal days. Otherwise, the number of cortical cells in both the Dex groups were significantly lower than that in the saline group on the 28th postnatal days (P < 0.05 in each). These findings suggest that the pretreatment with Dex protects the developing brain from HI injury through the suppression of the neuronal maturation. However, a decreased number of cortical cells may give rise to psychomotor retardation later.

Animals↗

PubMedDate not supplied

Severe neonatal nemaline myopathy with delayed maturation of muscle.

A Japanese infant with a severe neonatal form of nemaline myopathy showed features of muscle immaturity as well as rods in the biopsied quadriceps femoris muscle, and involvement of diaphragm was first confirmed at autopsy. The biopsied muscle showed numerous rods in 80% of muscle fibers, and an increased number of type 2C fibers (23.2%). Electron microscopic findings were characterized by the presence of many small, immature round fibers with central nuclei and sparse myofibrils, and an increased number of satellite cells in close association with the small muscle fibers, as well as numerous rod structures. These microscopic and electron microscopic findings are interpreted as immature muscle fibers. Maturational delay or arrest implies deprivation of a development promoting factor such as a neuronal signal. Severe involvement with numerous rods was demonstrated in both diaphragm and intercostal muscles at the time of the postmortem examination, compatible with the patient's respiratory failure.

Fatal Outcome↗

PubMedDate not supplied

Nonsurgical management of epidural hematoma in neonates.

We successfully treated 4 neonates with epidural hematoma by nonsurgical methods. In 3 of these infants, epidural hematoma was complicated by cephalohematoma and skull fracture; however, the epidural hematoma disappeared after aspiration of the dark red blood in the cephalohematoma, resulting in complete recovery without sequelae. In the remaining infant, epidural hematoma was complicated by intraventricular and subarachnoid hemorrhage and disseminated intravascular coagulation; the patient was successfully treated by conservative therapy, including exchange transfusion and repeated lumbar puncture with only mild motor difficulties remaining. Some patients with neonatal epidural hematomas can be managed by nonsurgical, conservative procedures, including cephalohematoma aspiration.

Hematoma, Epidural, Cranial↗

PubMedDate not supplied

Simple method for efficient production of hepatitis B virus core antigen in Escherichia coli.

To obtain good antigenicity and high purity of the hepatitis B virus core antigen (HBcAg) in large quantities without using the fused protein technique employed in recombinant DNA technology, a protein molecule with the same primary sequence as that of wild-type HBcAg (subtype adr) was directly expressed in Escherichia coli JM109 (DE3) using pGd1 expression vector. Purification of the expressed HBcAg yielded high-quality protein by means of simple purification steps, such as sonication, ammonium sulphate precipitation and heat treatment, before final purification by conventional ultra-centrifugation. The HBcAg preparation thus obtained contains small round particles similar in appearance to the HBcAg particles from the HBV-infected human liver tissue.

Escherichia coli↗