Effect of Arabinogalactans on Induction of White-Opaque Somatic Embryos of Avocado (Persea americana Mill.) cv. Duke-7.

The development of somatic embryogenesis in avocado (Persea americana Mill.) has been hampered by different chronic problems. One such problem is the low level of induction of white-opaque somatic embryos (WOSEs) during the process of obtaining full avocado plants. We detected the induction of multiple WOSEs promoted after the placement of three or four small WOSEs over the embryogenic callus of Duke-7. Among the other possible chemical inductors of the Arabinogalactans (AGPs), we identified a family of extracellular plant proteoglycans implicated in many aspects of the in vitro induction of somatic embryos (SE). We extracted AGPs directly from embryogenic cultures of avocado. When the induction/proliferation medium of embryogenic avocado calli (MS-0.1 mg L-1 Picloram) was supplemented with 1-2 mg L-1 AGP, the induction rate of good-quality WOSEs from the embryogenic callus increased significantly (more than ten times that of the control without AGP) and this effect persisted for at least five subcultures after the initial treatment with AGP. AGP also modified the texture and quality of the callus. The effect of AGP extends to other cultivars and proliferation media. Our objectives were to improve the induction of WOSEs and study the effect of AGP in the somatic embryogenesis of avocado.

Infantile hypertrophic cardiomyopathy of glycogenosis type IX: isolated cardiac phosphorylase kinase deficiency.

Glycogen storage disease confined to the heart due to cardiac phosphorylase kinase deficiency causes a fatal infantile cardiomyopathy. Cardiomegaly can be detected in utero and is progressive. Electrocardiographic and echocardiographic findings are characteristic but not specific; these include large QRS complexes, short PR interval, and a hypertrophic nonobstructive pattern. Conclusive diagnosis requires biochemical analysis of myocardium, which may not be possible premortem due to the amount of tissue required. Pathologic examination of a standard cardiac biopsy can provide a presumptive diagnosis. There is no current treatment except a heart transplant. Infants succumb to heart failure and/or respiratory compromise due to pulmonary compression. This is a rare entity; only three cases have been reported to our knowledge. We report two additional cases.

Bilaterally multicentric synchronous Wilms' tumor: successful conservative treatment despite persistence of nephrogenic rests.

We report a case of synchronous bilateral Wilms' tumor in a girl with incomplete Beck-with-Wiedemann syndrome and hemihypertrophy. Multiple small tumors were present in both kidneys. The initial diagnostic biopsy showed stage I monophasic blastematous Wilms' tumor of favorable histology, with multiple perilobar nephrogenic rests (nephroblastomatosis). By flow cytometry, tumor was diploid, with an S-phase fraction of 13.9%. Dactinomycin and vincristine were begun as per the National Wilms' Tumor Study IV (18 week course). After 1 month, only a single small lesion was evident, which persisted unchanged. Excisional biopsy 5 months after beginning chemotherapy showed entirely necrotic tumor but apparently unaltered nephrogenic rests. After completing chemotherapy, the child has done well, with normal renal function and no evidence of disease 3 years after diagnosis. Management of stage V Wilms' tumor is tailored to the individual case, being as conservative as possible to spare renal parenchyma. Given the high incidence of coexisting nephrogenic rests in bilateral Wilms' tumor, careful follow-up is required, as these potentially premalignant rests may resist chemotherapy.

Multinodular hyperplastic pannephric nephroblastomatosis with tubular differentiation: a new morphologic variant.

We report a case of bilateral nephromegaly detected prenatally with oligohydramnios. Delivered at 35 weeks, this black male infant rapidly developed renal failure, requiring dialysis. He lived 3 1/2 months. The kidneys were three times normal size and diffusely multinodular, with hypoplastic calyces, no corticomedullary demarcation, and no pyramids. Histologically, they revealed hyperplastic embryonal rests composed of tubules and ducts with prominent branching. The nodular rests were intermixed with areas of mature parenchyma, which showed prominent oxalosis. By flow cytometry, rests were diploid, with an S-phase fraction of 25.9%. The proliferation of embryonal collecting system analogs is attributed to excessively rapid and prolonged branching of the ureteric bud, dating from the fourth gestational month or earlier. This unique case may represent a new morphologic variant of universal nephroblastomatosis.

Bilateral hyperplastic nephromegaly, nephroblastomatosis, and renal dysplasia in a newborn: a variety of universal nephroblastomatosis.

A preterm boy was born at 34 weeks. Prenatal ultrasonography showed oligohydramnios, fetal ascites, large kidneys, and small thorax. He died 21 h after birth of respiratory insufficiency. Autopsy revealed Potter's-like facies, hypoplastic lungs, ascites, and bilateral nephromegaly (renal weight almost 10 times normal). The kidneys were finely nodular externally, solid, and cerebriform on cut section. Histologically, they showed a diffusely distorted architecture of jumbled lobules, hyperplasia of cortical-type tissue with inconspicuous proximal tubules, relative hypoplasia of medullary tissue, tubulointerstitial dysplasia, and perilobar nephrogenic rests. The renal features represent a variety of the universal or panlobar (also called pancortical or infantile) type of nephroblastomatosis. To our knowledge, this is only the third such case reported. In the brain, each lateral ventricle contained a yellow gelatinous mass. Histologically, the masses consisted of a pseudomyxoid matrix with delicate fibers and focal adipocyte clusters, all confined within choroid plexus. We consider these lesions fibrolipomatous hamartomas.