Festus O. Adebonojo

Monolayer cultures of disaggregated human adipocytes.

SummaryTwo theories have been advanced to explain the origin of adipocytes and both have experimental evidence in support. One theory proposed that adipocytes are specialized differentiated cells with specific lipid storage functions. The other held that they are unspecialized anlage cells which have the potential to store lipid depending on conditions. In an attempt to examine the little understood roles which these cells play in obesity and other abnormalities of lipid metabolism, disaggregated human adipocytes from infants and young children, free of stromal contamination, have been succesfully grown in culture. The details of the techniques used, and some peculiar morphological characteristics of these cells in culture, are described.

Artificial vs Breast Feeding Relation to Infant Health in a Middle Class American Community

In a comparative study of 113 infants of affluent and well-educated par ents in the same environment, 52 were breast fed and 61 artificially fed. No significant differences could be found between the two groups with respect to a variety of standard clinical measures of health and wellbeing. Where poor hygiene is not a factor, mothers milk per se appears to offer no advantage over present-day artificial infant foods.

Monolayer Cultures of disaggregated human adipocytes

Two theories of adipose cell origin have been proposed. One suggests that they develop from specialized anlage whose cells spread throughout the body and accumulate fat. The other holds that they form by accumulation of fat in unspecialized cells of connective tissue. Each theory has some experimental support.Animal adipose cells have been grown readily in tissue culture but, human adipocytes have been more difficult to grow. This study was undertaken in an effort to understand the origin of adipocytes and their relationship to obesity. Disaggregrated adipose cells taken from human infants of different ages were grown in tissue culture. Under conditions of culture used the cells changed from their usual spherical to a fibroblast appearance, gradually lost intracellular lipids, then divided. Adipocytes from older children also changed shape, lost intracellular lipids more slowly but were not observed to divide.These findings, while shedding no light on the origin of adipocytes, suggest that their ability to divide may depend, at least in tissue culture, on the donor age.

Acid and neutral lipases of cultured adipocytes of infants and children.

Summary: In order to determine whether the mobilization of intracellular triglycerides observed in cultured human adipocytes is associated with changes in the activities of acid and neutral lipases, the activities of both enzymes were measured weekly on cultured adipocytes for several months. The activity of acid lipase was initially very low, but rose to levels 40 times the original activity within 3 months. The activity of neutral lipase decreased rapidly within the first 2–4 weeks and remained at approximately 25% of original levels thereafter.Speculation: There is increasing evidence that the human adipocyte is highly specialized and that it is derived from a stromal precursor present in the adipose tissue. The cell has the capacity to acquire in culture the properties of the precursor, as evidenced by the appearance of acid lipase and disappearance of neutral lipase. We submit that the low level of acid lipase in the adipocyte is related to its lipid storage function. It remains to be proven that it is not primary to the differentiation of the adipocyte from its precursor. Furthermore, we speculate that a direct biochemical relationship exists between the neutral lipase and intracellular triglyceride stores in the adipocyte.

Congenital Dislocation of the Hip—Diagnostic Screening and Treatment A Comparative Study of Two Populations of Infants and Children

To understand why congenital dislocated hip (CDH) was diagnosed late (mean age: nine months) in children admitted to the Childrens Hospital of Philadelphia (CHOP), 714 consecutive CHOP admissions, aged zero to two years, and 947 consecutive newborns delivered at the Hospital, Uni versity of Pennsylvania (HUP) were examined for CDH. The expected frequency of CDH was found at HUP. At CHOP, the children had a higher incidence of CDH, many with associated congenital anomalies, their hips were more difficult to examine, the hospital records contained few references to hip examinations. Had these childrens hips been formally examined at birth, the delay in diagnosis might have been eliminated and treatment might have been easier and more successful.

Primary Exogenous Obesity: A Conceptual Classification

* Children’s Hospital of Philadelphia, 34th and Spruce Streets, Philadelphia, Pa. 19146, and Upiversity of Pennsylvania School of Medicine, Philadelphia, Pa. 19104. PRIMARY EXOGENOUS OBESITY has been defined simply as a state of excess adipose tissue in the body. 1.2 But excess adipose tissue is difficult to quantify. With cadavers, Bray, et al. ~ have suggested that obesity is present when fat content exceeds 25 per cent of body weight in males and 30 per cent in females. Such determinations are difficult in live humans.

Enzymatic Adaptations by Cultured Adipocytes of Human Infants and Children: Effect of Obese Serum on the Activities of Lactate-, Malate-, and Glucose-6-phosphate Dehydrogenases

Extract: To determine whether there are any biochemical characteristics which distinguish human adipose cells from human skin fibroblasts, assays of lactate dehydrogenase with pyruvate as substrate (LDH-P), malate dehydrogenase (MDH), and glucose-6-phosphate dehydrogenase (G6PDH) were done on both cell types after they had been successfully adapted to artificial medium in tissue culture and also while they were growing temporarily in serum from an obses individual. After undergoing transformation to a fibroblastlike appearance, the adipose cells (adipofibroblasts) contained significantly more of each enzyme than did the initial adipose cell isolates. The level of activities of LDH-P and G6PDH increased to the same levels as in skin fibroblasts (Table 2); however, MDH activities rose to much higher levels than those found in skin fibroblasts (Table 2).In obese serum, activities of LDH-P did not significantly change but the activities of MDH and G6PDH dropped sharply in adipofibroblasts (P < 0.005, Table 2 and Fig. 5), whereas in cultures of skin fibroblasts, only the activities of G6PDH dropped significantly (P < 0.025 Table 2), the other enzyme activities being unchanged. It is concluded that, on the basis of the biochemical behaviors of these two cell lines in culture, adipose cells are biochemically different from skin fibroblasts and are not to be regarded as just fibroblasts with lipid-storing ability.Speculation: Some evidence suggests that adipose cells are derived from stromal precursors present in the adipose depot. The data presented in this study suggest that, although cultured adipose cells may be similar in some respects to skin fibroblasts, they have some important differences from skin fibroblasts. The differences may reflect the fact that, as a consequence of differentiation, enzymatic patterns develop which determine how they will perform their special functions of lipid synthesis, storage, and release, It is argued that adipocytes and their precursors are not fibroblasts which happen to be able to store lipids.

1187 NEUTRAL LIPASE (NL) ACTIVITY IN BOVINE AND HUMAN ADIPOSE TISSUE (AT)

Using 14C triolein as substrate, the activity of NL in bovine and human AT was determined in a) the crude extract in PBS pH 7.4, b) the 105,000 xg supernatant (S105 fx)> c) the pH 5.2 acetic acid precipitate redissolved in tris-Hcl pH 7.4 (pH 5.2 ppt), d) the pH 5.2 ppt solubilized in 3mM Nonadet P40 (sol. pH 5.2 ppt) and e) the aqueous fraction of the pH 5.2 ppt (Aq. Fx.). The results shown indicate that most of the original activity was recoverable in the S105 Fx. It also shows; that in contrast to published rat results, NL is several times more active in rat than in either bovine or human AT. Further while, in rat, there was a 35-fold purification achieved at the pH 5.2 ppt stage, there was only a 2-fold purification in the bovine and a 4-fold purification in the human AT at that stage. Solubilization with Nonadet P-40 appears to render both enzymes less measurable by the assay method employed. These data suggest that NL in human and bovine AT are more alike and differ in some important respects from NL in rat AT.

912 STUDIES RELATED TO THE CRISIS EPISODES IN SICKLE CELL PATIENTS

In this study we have measured a variety of hematogical parameters in 17 sickle cell disease (SCD) patients (mean age: 35 years) for a period of 30 months. Several hematological parameters were measured under conditions of vaso-occulsive crisis as well as in the steady state noncrisis period. The mean serum calcium content (mg of calcium per dl) was found to be less (P < 0.05) during crisis (8.24 ± 0.73, N = 7) than during the non-crisis states (8.81 ± 0.43, N = 15). This decrease in serum calcium may be the result of calcium influx into Hb SS-erythrocytes. Irreversibly sickled Hb SS-erythrocytes are known to have a particularly high calcium content. Fibrinogen levels were also found to be much higher (P < 0.01) in the crisis state (426±195 mg/dl, N = 3) compared to the noncrisis state (236 ± 47 mg/dl, N = 14). Measurements of serum LDH and of oxygen saturation (p-50 per cent) and blood gases were not significantly different in the two states (crisis vs steady state). There is an increased shift to the right of the optical density of sickle hemoglobin during crisis compared to the steady state. Measurement of the optical density of sickle hemoglobin may be useful in predicting the frequency of sickle cell crisis in some patients.

607 NUTRIENT CHANGES IN CRITICALLY ILL CHILDREN ON TOTAL PARENTERAL NUTRITION

In the critical care of children it is increasingly necessary to use total parenteral nutrition. Daily intakes of fluids, calories (amino acids, dextrose, fat), minerals and vitamins were prospectively monitored in 17 sick children aged 6 mos. to 14 years during 24 episodes of total parenteral nutrition (TPN). Essential laboratory observations were also prospectively made. Twelve children had one, 3 had two and 2 had three episodes of TPN administrations. Duration of TPN for children weighing less than 10 kg was 13±3 days (mean ±SD) and for those over 10 kg, it was 10±2 days (mean ± SD). To maintain normal serum electrolytes, mean daily intakes for most minerals remained constant throughout TPN administration, except for sodium and chloride where the mean daily requirements decreased from 4.0 and 4.4 meq/kg respectively to 2.6 and 2.8 meq/kg respectively at 10-12 days. Moderate elevations in values of SGOT/SGPT were observed in most patients between 7 and 10 days and LDH and CPK between 17 to 20 days of treatment. Significant biphasic elevations in blood sugar was noted at days 5 to 7 and days 18 to 21, when the mean blood sugar rose from 100 mg/dl to 147 mg/dl and 132 mg/dl respectively. The mean daily requirements for fluids, calories and vitamins did not change significantly once optimal intakes have been achieved. In 3 children, serum levels of magnesium, zinc and copper were carefully monitored and no changes were found.