Physiology of the ECL cells.

The enterochromaffin-like (ECL) cells of the oxyntic mucosa (fundus) of the stomach produce, store and secrete histamine, chromogranin A-derived peptides such as pancreastatin, and an unanticipated but as yet unidentified peptide hormone. The cells are stimulated by gastrin and pituitary adenylate cyclase activating peptide and suppressed by somatostatin and galanin. Choline esters and histamine seem to be without effect on ECL cell secretion. The existence of a gastrin-ECL cell axis not only explains how gastrin stimulates acid secretion but also may help to explore the functional significance of the ECL cells with respect to the nature and bioactivity of its peptide hormone. From the results of studies of gastrectomized/fundectomized and gastrin-treated rats, it has been speculated that the anticipated ECL-cell peptide hormone acts on bone metabolism.     

Behaviour, natural history, and annual cycle of the Henderson Island rail Porzana atra (Aves: Rallidae)

The little known endemic Henderson Island rail (or Henderson rail) Porzflna atra , inhabits forest on the coastal plain and upraised plateau of Henderson Island. Rails were studied for 15 months from January 1991 to March 1992. The population was estimated at c. 6200 individuals living in pairs or cooperative groups of 3–4 adults on territories averaging about 1 ha. Two or three eggs were laid in covered or open nests near the ground from mid-July to mid-February. Up to five consecutive nesting attempts were made in cases where eggs or young chicks were lost. Adults laid a second clutch when chicks were fully feathered at about one month of age. Both sexes incubated and helped rear the young. Older chicks sometimes helped feed younger siblings. Dispersal of juveniles from the natal territory took place in April. Adult birds underwent a rapid, simultaneous post-nuptial moult of the remiges in February-April; the post-juvenile moult involved body feathers only. Data on morphometries, breeding ecology, courtship behaviour and voice are compared with available information for the spotless crake P. tabuensis , the Henderson rail's closest relative and probable ancestor. These comparisons provide some information on how these two taxa have differentiated since rails arrived on Henderson Island some time in the last 380000 years.     

An experimental study on the effect of rigid fixation on the developing craniofacial skeleton

Rigid fixation of the craniofacial skeleton has proven of great value in adult orthognathic and traumatic reconstructive surgical procedures. This technique has gained increased acceptance in the surgical treatment of infants and young children with congenital malformations, despite the fact that its effects on subsequent craniofacial growth are unknown. To examine this question, an experimental model using 25 young kittens was developed to compare rigid fixation with conventional wire fixation, with and without osteotomy. Our findings demonstrate a regional restriction of growth in the developing craniofacial skeleton when both wire and plate and screw fixation are utilized in concert with osteotomy. Further, a compensatory growth was observed in individual animals when plate fixation was utilized that was not seen in the wire-treated group. This suggests that there is a dynamic growth interaction between restriction and compensation in this setting.     

The healing of facial bone fractures by the process of secondary union

The mechanism of healing of facial bone fractures was investigated in a rabbit model. Twelve New Zealand white rabbits underwent surgically induced fractures of the right infraorbital rim and fracture ostectomies (4 to 5 mm) of the left infraorbital rim. Animals were sacrificed 2, 4, and 8 weeks postfracture. Bone, including periosteum, obtained from each fracture or fracture osteoctomy site was divided longitudinally for hematoxylin and eosin staining, fluorescent microscopy, microangiography, and microradiography. Sequential fluorochrome labels of oxytetracycline (30 mg/kg), alizarin complexone (30 mg/kg), DCAF (20 mg/kg), and xylenol orange (90 mg/kg) were administered 24 hours preoperatively and at 1, 2, 4, and 8 weeks postfracture. All fracture and fracture ostectomy sites demonstrated vascular ingrowth, mineralization, and woven bone formation by 2 to 4 weeks postoperatively, beginning with a cartilage precursor. Subsequently, the woven bone was replaced with remodeled lamellar bone, resulting in complete bony healing by 8 weeks postoperatively. These steps were substantiated by microscopic, microradiographic, and radiologic examination of the specimens. This study demonstrates that fractures of the facial bones in a rabbit model heal by a process of new bone formation that resembles secondary union in endochondral bones.     

Angiographic diagnosis of agenesia, aplasia and hypoplasia of kidneys in children]

Problems of the diagnosis of congenital renal developmental defects (CRDD) still continue to present a certain interest. Basing on their own experience in the diagnosis of CRDD in 188 of 527 children with renal pathology, the authors arrived at a conclusion that intravital diagnosis of renal aplasia was not only possible with the help of angiography, but also extremely necessary because agenesia and aplasia were two separate entities in their genesis, limiting the potentialities of reconstructive operations in aplasia. Hypoplasia in children was very frequent and was characterized by 5 types of the angiographic picture. Analyzing the state of the contralateral kidneys in CRDD, the authors considered some features of compensatory hypertrophy.     

Radiologic pulmonary manifestations in patients with HIV virus infection]

Altogether 155 patients with a newly detected positive reaction to HIV (a human immunodeficiency virus) were investigated in the Republic of Burundi. Chest x-ray was done in 80 of them. Pulmonary tuberculosis was diagnosed in 2 of them, pneumonia (chronic, interstitial and bronchial)--in 15. Enhancement and deformity of lung marking were detected in 45 patients (coincidence with clinical signs of acute bronchitis was found but in 5 of them). A conclusion has been made of interstitial pneumonias being typical of HIV-infected patients and of frequent enhancement of lung marking in the preclinical stage of AIDS.     

Stimulation of calcium intake by growth-hormone-releasing-hormone in GH3 cells]

The effect of GH-RH in the intra-cytosolic free Ca2+ concentration was studied in GH3 cells. To this end, we have used microspectrofluorimetry performed on single cells. We show that 60% of cells respond to a brief application of 100 nM GH-RH by an increase of their [Ca2+]i (mean increase 100% over basal values). This response which is blocked by calcium channel inhibitors results from an increased influx of Ca2+ ions from the external medium.