Serial lateral hypothalamic destruction: Infancy and adulthood

Male and female albino rats sustained unilateral destruction of the lateral hypothalamic area as infants (10 days of age) or as adults (150 days of age). Also, rats receiving unilateral destruction of the lateral hypothalamic area as infants had their contralateral (intact) lateral hypothalamic area destroyed at 150 days of age, i.e., two-stage serial lateral hypothalamic area destruction separated by 140 days, thereby producing bilateral destruction. The animals were tested for homeostatic regulatory capacity. Loss of one lateral hypothalamic area during adulthood produced greater regulatory deficits than were produced by the loss of one during infancy. These results suggest that the intact lateral hypothalamic area of infant rats has greater capacity to maintain function than does the same intact area of adults.The regulatory deficits produced with two-stage lateral hypothalamic area destruction (one lateral hypothalamic area destroyed during infancy followed by destruction of the contralateral area during adulthood) were nearly identical to the deficits produced with one-stage bilateral destruction, i.e., the regulatory deficits were persistent and severe in spite of the fact that 140 days separated the two lesions.Thus, infant rats can maintain approximately normal regulatory capacity with one intact lateral hypothalamic area. This “sparing of function” was due to the intact lateral hypothalamic area, as its subsequent destruction produced more profound regulatory deficits than were produced with unilateral destruction of the lateral hypothalamic area sustained during adulthood. These results suggest that the “plasticity” of the infant lateral hypothalamic area is greater than that of the adult and that infantile “plasticity” is manifest by the capacity of the intact lateral hypothalamic area to subsume the function of the damaged contralateral area.     

Pseudoaneurysms complicating organ transplantation: roles of CT, duplex sonography, and angiography

In a retrospective study of proved pseudoaneurysms (PAs) in 15 patients with transplanted organs (11 liver, three kidney, one pancreas), the results of computed tomography (CT), duplex sonography, and angiography were reviewed. Of the 15 cases of PA, eight occurred at the arterial anastomosis and seven were nonanastomotic. Three of the eight anastomotic PAs were caused by infection. Of the seven nonanastomotic PAs, four were caused by percutaneous biopsy, two were caused by infection, and one was of undetermined cause. In nine (60%) of the 15 patients the PAs were incidentally detected at imaging studies performed for other reasons. Diagnosis requires a high degree of suspicion. CT was performed in nine cases and duplex sonography in ten. The diagnosis of PA was made with CT in six (67%) patients and with duplex sonography in five (50%). CT and duplex sonography could not enable diagnosis when the PA was small, when the arterial anastomosis was not included in the field of study, or when enhancement with intravenously administered contract material was suboptimal. Angiography depicted the PAs in all 15 patients. In three liver transplant recipients with gastrointestinal tract bleeding, the causative PAs were detected only with angiography.     

Percutaneous transluminal angioplasty: the treatment of choice for renovascular hypertension due to fibromuscular dysplasia

Twenty-three renal artery stenoses in 21 hypertensive patients, caused by fibromuscular dysplasia, were treated with percutaneous transluminal angioplasty (PTA). Follow-up over a period of 1 to 30 months, including angiography, renal vein renin assay, and radionuclide flow studies, was performed in 8 patients, each with one stenosis. Dilatation was initially successful in all cases and was successfully repeated in 1 case. The mean systolic pressure decreased by 61.81 mm Hg and the mean diastolic pressure by 36.28 mm Hg in response to treatment. Thirteen patients were cured, 8 were felt to have better control of blood pressure on medication, and there was no failures. This study demonstrates that PTA is a clinically effective method of treating renovascular hypertension due to fibromuscular dysplasia.     

The ontogeny of feeding and drinking: Effects of early brain damage

Research concerned with the effects of early brain damage upon the ontogeny of feeding and drinking behaviors is described. The neural areas discussed are the olfactory bulbs, frontal cortex, lateral hypothalamic area, substantia nigra-nigrostriatal bundle, reticular formation, and central gustatory structures. The effects of early (infancy) and late (adulthood) brain damage upon consummatory behaviors are described, and critical ages are defined. For each neural area, the critical age is the age during development when damage to a specified neural area produces consummatory behavior alteration which is equivalent to consummatory behavior alteration produced when the neural area is destroyed in adults. Critical ages were found to differ for different neural areas, e.g., 7–8 days of age for lateral hypothalamic area, 60 days of age for frontal cortex. These critical ages may serve to signal the ontogenetic onset of function of neural substrates of consummatory behaviors and/or neural plasticity preserves function when damage occurs prior to the critical age.     

Sucking behaviors of normal 3-day-old female neonates during a 24-hr period

Feeding behaviors were measured during six feeding sessions distributed throughout a 24-hr period in 10 normal 3-day-old female infants. Infants were individually videotaped during feeding sessions at 13:00, 17:00, 21:00, 01:00, 05:00, and 09:00 hours. Total mealtime, nutritive sucking time, pause time, number of nutritive sucks, and amounnt of nutrient consumed were measured. None of these feeding variables were affected by the time of day an infant was fed. Maternal interactions with their infants such as auditory stimulation, caretaking touches or tender touches were unaffected by the time of a feed. These maternal behaviors did not correlate with any of the feeding variables. These findings suggest that 3-day-old infants experiencing routine nursery care do not express specific day-night feeding differences and that certain maternal behaviors do not influence the infants' feeding pattern.