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Biomedical subjects

Y Finkel

Publications and source records attributed to Y Finkel.

52 records · Page 3Linked to original sources

Mechanisms for colonic sodium transport during ontogeny: loss of an amiloride-sensitive sodium pathway.

Net colonic sodium and fluid absorption is higher in suckling and weanling rats than in adult rats. This study was undertaken to investigate the mechanisms behind these differences. In vivo perfusion of the colon was performed in 14- to 80-day-old rats. Net Na and water uptake decreased exponentially from 14 to 80 days of age. Na uptake was 402 +/- 73 micrograms Eq/min/g DT in 20-day-old rats and 116 +/- 6 mu Eq/min/g DT in 40-day-old rats. After amiloride treatment, net Na transport was reversed to net secretion (-79 +/- 36 mu Eq/min/g DT) in 20-day-old rats. Amiloride had no effect on the net Na transport in 40-day-old rats. cAMP stimulation significantly increased the net Na uptake in 20-day-old rats and significantly reduced the net Na uptake in 80-day-old rats. cAMP did not increase the net uptake in amiloride-treated 20-day-old rats. We conclude that there are both quantitative and regulatory changes in the pathways for colonic Na transport during development, and we speculate that the large amiloride-sensitive sodium uptake in the young colon is adaptive and contributes to the sodium accretion necessary for rapid growth during late postnatal development.

Aging↗

Vincristine neuropathy and a Guillain-Barré syndrome: a case with acute lymphatic leukemia and quadriparesis.

A 3 1/2-yr-old boy with acute leukemia rapidly developed quadriparesis during induction treatment that included vincristine. Accompanying the paralysis, spinal fluid protein was increased. This has not previously been associated with vincristine neuropathy. In addition to leukemia, we suggest that the patient had the Guillain-Barré syndrome, potentiating the neurotoxicity of vincristine.

Cerebrospinal Fluid Proteins↗

Prolactin, AVP, angiotensin II, corticosterone and aldosterone in the rat during weaning.

In the rat significant changes in the control of body water and electrolyte homeostasis take place during the weaning period (16-24th day of life). This study was performed to analyse how the serum levels of hormones that are known to modulate body water homeostasis change during that period. The serum levels of aldosterone, corticosterone and prolactin increased significantly from 10 to 20 days, whereas those of arginine vasopressin were the same between 10 days and 20 days but increased significantly from 10 to 40 days. Serum levels of angiotensin II increased significantly from 10 to 20 days but decreased from 20 to 40 days, at which time they were significantly lower than in 10-day-old rats. In prolonged-suckling rats, that is, rats which suckled until the 20th day of life, the serum levels of corticosterone, aldosterone and prolactin were somewhat lower than in control rats and those of prolactin were not detectable at 16-20 days. It is concluded that important changes in the serum levels of hormones that regulate body water and electrolyte homeostasis take place during weaning. The postnatal increase in the serum levels of corticosterone and aldosterone is independent of weaning to solid food. The prolactin serum levels seem to be influenced by the length of the nursing period.

Age Factors↗

Oral absorption of flucloxacillin in infants and young children.

The bioavailability of flucloxacillin (Heracillin) following oral administration was determined in infants and children. After a dose of 12.5 mg/kg, peak concentrations were achieved at 60 min. which declined rapidly and were low in older children only 4 hours afterwards. Infants below 6 months of age showed a better absorption when given the mixture than older children. Older children achieved higher plasma concentrations when given tablets than when given equal doses of the mixture. There was no difference in the concentration when the dose was given to the subject when fasting, or with breakfast.

Administration, Oral↗

Role of aldosterone for control of colonic NaKATPase activity in weanling rats.

Experiments were performed to examine how aldosterone modulates colonic NaKATPase activity during the weaning period. NaKATPase activity was determined in proximal and distal colon in control rats aged 16, 20, and 40 days, in rats aged 20 and 40 days fed low sodium diet for 4 days and in 20-day-old rats adrenalectomized on day 16. In some protocols net sodium and water transport was determined with in vivo perfusion technique. In control rats colonic NaKATPase activity increased significantly between day 16 and 20. This increase was abolished by adrenalectomy but restored by aldosterone substitution, 5 micrograms/100 g body weight/12 h. No significant increase in NaKATPase activity occurred between day 20 and 40. Serum levels of both aldosterone and of corticosterone were low until day 14 and increased to peak level at day 18-20. In 20- and 40-day-old rats fed a low sodium diet, NaKATPase activity increased significantly in proximal and distal colon in both age groups but the increases were significantly greater in the 20- than the 40-day-old animals. A low sodium diet increased serum aldosterone, but not serum corticosterone levels in both age groups: also the low sodium diet significantly increased net sodium and water transport in 20- but not in 40-day-old rats. Aldosterone is of physiological importance for the regulation of NaKATPase activity in the colon at the time of weaning. The immature colon may have an enhanced sensitivity to aldosterone.

Adrenalectomy↗

Development of colonic fluid and electrolyte transport: influence of weaning pattern.

The purpose of this study was to investigate the normal postnatal development of electrolyte and water transport in the large intestines of rats aged 10-20 days, to focus on the events taking place around the time of weaning, and to study the influence of different feeding patterns at the time of weaning on the normal development of the transport mechanisms in the large intestine. The net absorption of sodium, potassium, and water was investigated by using in vivo luminal isotonic perfusion in rats aged 12-40 days. The activity of the active transport enzyme Na-KATPase in the colonic mucosa of rats aged 10-40 days was determined. We found a significant decrease in the net absorption of electrolytes and water that was greatest around the time of weaning. Since the NaKATPase activity was lower in 10-16-day-old rats than in 40-day-old rats, we suggest that the high sodium and water uptake in the colon of suckling rats is independent of the sodium pump. Changes in the feeding patterns around the time of weaning, such as prolonged suckling, were associated with a significantly higher net absorption of electrolytes and water than in rats that were normally weaned at 20 days of age. The Na-KATPase activity was not significantly influenced by the weaning pattern.

Animals↗

The influence of the sweetening agent on the oral absorption of penicillin V.

Plasma concentrations of Penicillin V were determined following oral administration in children of mixtures containing different sugars as sweetening agents. Significantly higher peak plasma concentrations and area under the curve were found with sacharose than with sorbitol. Mixtures containing fructose gave intermediate values.

Administration, Oral↗

The effect of food on the oral absorption of penicillin V preparations in children.

The oral absorption of pc V in different preparations, given at various times before and after a meal, was investigated in children with upper respiratory infections. The best absorption with respect to peak concentration was observed when potassium pc V (Calciopen) was given after at least two hours of fasting with no food intake within the following hour. Shorter periods of fasting (1, 1/2, 0 hrs) before drug intake resulted in significantly lower plasma concentrations. When drug intake was followed by a meal, the absorption was also decreased to some extent. When pc V was given in an oil suspension (Fenoxypen), or in a small volume (Roscopenin) together with a meal, the peak concentration was significantly lower than when pc V was given in an aqueous solution with a larger volume (Calciopen).

Administration, Oral↗

Plasma levels of metrifonate and dichlorvos during treatment of schistosomiasis with bilarcil.

Metrifonate (0,0-dimethyl-[1-hydroxy-2,2,2-trichloroethyl]-phosphonate), and its rearrangement product dichlorvos (2,2-dichlorovinyl dimethyl phosphate) (DDVP), were studied in plasma from two patients with schistosomiasis who were treated with Bilarcil. A mass fragmentographic technique was used. Isotopic variants of the substances were used as internal standards and to compensate for DDVP formed during the workup procedure. The results were related to erythrocyte and plasmacholinesterase determinations. The method described makes it possible to study pharmacokinetics in man and to relate this information to therapeutic effects. It is proposed that metrifonate acts as a slow release formulation for DDVP.

Adult↗

The effect of a 1-hour training program on the incidence of bacteremia in pediatric patients receiving parenteral nutrition.

The effect of a 1-hour nurse training program on the frequency of bacteremia in patients receiving parenteral nutrition was evaluated in a pediatric tertiary center. All of the nurses had previous instruction on aseptic techniques in nursing school. The current program focused on aseptic management of intravenous catheters and implanted subcutaneous ports in patients receiving parenteral nutrition (PN). One hundred eighty-four nurses had a 1-hour training session in groups of three to five. The frequency of bacteremia in children receiving PN was not reduced (9.2% versus 8.9%), and there was no significant difference in time from the start of PN to the diagnosis of bacteremia (P = 0.31). The authors conclude that a 1-hour training session for the nursing staff was not sufficient. It is suggested that staff training for prevention of bloodstream infections associated with intravascular devices should cover a wider range of topics and take place over a longer period of time.

Bacteremia↗

Morphometric and functional studies of proximal and distal colon in young and adult rats.

Net sodium and fluid absorption in the colon is higher in young than in adult rats. The mechanism behind the high absorption in young rats is not well understood. In this study, we investigated the structural and functional properties of the proximal and the distal colon in 20- and 40-day-old rats. The surface area of the mucosa along the luminal surface of the gut in relation to the mucosal volume (surface density) was determined by morphometry. Net sodium and water absorption was determined by in vivo perfusion experiments. The surface density of the mucosa was greater in the proximal than in the distal colon in both 20- and 40-day-old rats. No developmental change in the surface density of the mucosa occurred between 20 and 40 days of age, however, in either the proximal or distal colon. Net sodium and fluid absorption per unit of weight were higher in both segments in 20- than in 40-day-old rats, and higher in the distal than in the proximal colon in 40-day-old rats. We conclude that other factors than the absorptive area are responsible for the decrease in the net colonic sodium and fluid absorption observed during late postnatal development and for the differences in sodium net absorption between the proximal and distal colon in 40-day-old rats.

Aging↗

Home parenteral nutrition (HPN) in children in Sweden.

This study represents a national survey of all children identified on home parenteral nutrition (HPN) in Sweden via all hospital pharmacy distributors. Indications for HPN from this sample were chronic intestinal pseudo obstruction (n = 5) and short bowel syndrome (n = 7). Linear growth was normal in 9 children and all school-age children attend classes at age-relevant levels. Families appear to have adapted well. There was one divorce among these families, and over the course of the HPN child's illness, younger siblings were born.

Adaptation, Psychological↗