Comparison of a beta-lactam alone versus beta-lactam and an aminoglycoside for pulmonary exacerbation in cystic fibrosis.

UNLABELLED: We determined whether a beta-lactam and an aminoglycoside have efficacy greater than a beta-lactam alone in the management of a pulmonary exacerbation in patients with cystic fibrosis. STUDY DESIGN: Azlocillin and placebo or azlocillin and tobramycin were administered to 76 patients with a pulmonary exacerbation caused by Pseudomonas aeruginosa in a randomized double-blind, third-party monitored protocol. Improvement was assessed by standardized clinical evaluation, pulmonary function testing, sputum bacterial density, sputum DNA content, and time to the next pulmonary exacerbation requiring hospitalization. RESULTS: No significant difference was seen between the 2 treatment groups in clinical evaluation, sputum DNA concentration, forced vital capacity, forced expiratory volume in second 1, or peak expiratory flow rate at the end of treatment (33 receiving azlocillin alone and 43 both antibiotics); adverse reactions were equivalent in each group. Sputum P. aeruginosa density decreased more with combination therapy (P =.034). On follow-up evaluation, an average of 26 days after the end of treatment, all outcome indicators had worsened in both groups. Time to readmission for a new pulmonary exacerbation was significantly longer in the group receiving azlocillin plus tobramycin (P <.001). Treatment-emergent tobramycin resistance occurred in both groups and was more frequent with combination therapy. CONCLUSION: We conclude that the combination of a beta-lactam and an aminoglycoside produces a longer clinical remission than a beta-lactam alone and slightly better initial improvement.

The Kentucky medical curriculum. A response to the call for educational reform: a GPEP report card.

The resources of an important educational grant provided by the Robert Wood Johnson Foundation, as well as designated local college and medical center funds, provided support for the renewal of the undergraduate medical education program at the University of Kentucky College of Medicine. The fully revised medical curriculum, adapted to changing professional and societal needs and completely in place by the 1994-95 academic year, was influenced by the recommendations of the General Professional Education of the Physician (GPEP) Report, issued by the Association of American Medical Colleges in 1984. This paper details each of the student-centered curricular changes in the context of the GPEP recommendation that it particularly addresses.

Physicians for the 21st century: implications for medical practice, undergraduate preparation, and medical education.

Changes in medical education and the practice of medicine have resulted from the push for both education and health care reforms. Undergraduates planning application to medical school should broaden their preparation to include communications, computers, economics, and multicultural educational experiences. To prepare graduates for medical practice in the new millennium, the University of Kentucky College of Medicine has implemented a new curriculum focusing on integration of basic and clinical sciences, primary care in ambulatory sites, health promotion and disease prevention, and attention to the ethical, social, psychologic, and financial impact of disease upon the patient, family, and society.

Chloroplast DNA diversity among wild and cultivated members of Cucurbita (Cucurbitaceae).

Cladistic analysis of 86 chloroplast DNA restriction-site mutations among 30 samples representing 15 species of Cucurbita indicates that annual species of the genus are derived from perennials. The Malabar Gourd, C. ficifolia, is placed as a basal, sister taxon relative to other domesticated species and allied wild-types. The pattern of variation supports three species groups as monophyletic: (1) C. fraterna, C. pepo, and C. texana, (2) C. lundelliana, C. martinezii, C. mixta, C. moschata and C. sororia, and (3) C. foetidissima and C. pedatifolia. Domesticated samples representing subspecies of C. pepo are divided into two concordant groups, one of which is allied to wild-types referable to C. texana and C. fraterna. The data failed to resolve relationships among cultivars of C. moschata and C. mixta and their association to the wild C. sororia. The South American domesticate, C. maxima, and its companion weed, C. andreana, show close affinity and alliance to C. equadorensis.

Effects of resection on absorption and secretion of divalent cations by small intestine of rat.

Resection increases villus height and crypt depth of remaining intestine. We examined functional consequences of resection by measuring absorption of strontium and secretion of calcium and magnesium by proximal and distal segments remaining after resecting 70% of mid small intestine. Compared with the transected control group, resection decreased strontium absorption per unit weight of mucosa (specific absorption) in the proximal segment. The decreased specific absorption was compensated by increased mucosal growth in the resected group so that absorption per unit length of segment (per cm) was the same in both groups. Resection increased secretion of calcium and magnesium by 66% per unit weight of mucosa and by 145%/cm in the distal segment. Comparing proximal with distal segments in the resected group, secretion was greater in distal for calcium and in proximal for magnesium. Intestinal resection causes responses in absorption and secretion of divalent cations important in mineral homeostasis.

Effects of phospholipid or cholesterol enrichment of rat intestinal brush border membrane on membrane order and transport of calcium.

Calcium uptake by brush border membrane vesicles from rat small intestine measured under initial rate conditions comprises both saturable and nonsaturable components. Because the brush border is a lipid bilayer and may be sensitive to changes in membrane lipid, vesicles were treated with liposomes to enrich phospholipid (PL) or cholesterol (C) content above that of the control (Reference) vesicle. The effects of the changes in lipid composition on membrane fluidity were determined from fluorescence anisotropy (r) of diphenylhexatriene. Compared with Reference vesicles, liposome-treated vesicles showed decreased Vmax for saturable and KD for nonsaturable uptakes. Liposome treatment changed vesicle phospholipid composition compared with Reference vesicles. Liposome-treated vesicles had similar phospholipid composition but differed in greater cholesterol content of C- compared with PL-vesicles. Mean Vmax and KD were lower in C- than PL-vesicles, but the difference did not reach statistical significance, although fluidity was significantly lower in C- than PL-vesicles. The mechanism of inhibition of saturable calcium uptake in PL- and C-vesicles was uncompetitive. Thus, lipid composition is crucial for determining calcium uptake: any change from native lipid composition decreased transport. Fluidity, measured by the conventional probe diphenylhexatriene, did not correlate with calcium uptake by Reference compared with liposome-treated vesicles.

Calcium uptake by brush-border membrane vesicles from the rat intestine.

Uptake of calcium by brush-border membrane vesicles from rat small intestine is composed of saturable and nonsaturable components. We studied regulation of calcium uptake using the divalent cations strontium, a foreign ion that mimics calcium biologically and magnesium, a physiologically important ion that resembles calcium physically, although not biologically. Strontium present outside the vesicle inhibited saturable calcium uptake competitively, consistent with binding to the transporter at the same site as calcium. Strontium inside the vesicle accelerated saturable calcium uptake from the outside (countertransport), also consistent with binding to the same transporter site as calcium. Thus the calcium transporter shows functional characteristics of a mobile carrier. In the uptake medium (extracellular), magnesium was a noncompetitive inhibitor of saturable calcium transport, consistent with a regulatory role in calcium uptake by binding to the transporter at a locus other than that for calcium. Magnesium at 1 mM concentration inside the vesicle had no effect on saturable calcium uptake and a high concentrations functioned as a week uncompetitive inhibitor. Thus intracellular magnesium appears to have no major role in regulating saturable calcium uptake at the brush border of the enterocyte.

Calcium transport in the spontaneously hypertensive rat is responsive to vitamin D.

Intestinal calcium transport rate and response to treatment with a vitamin D agonist [24,24-difluoro-1,25-dihydroxycholecalciferol, F2-1,25-(OH)2D3)] were studied in the spontaneously hypertensive (SH) rat-Wistar Kyoto (WKy) rat model of hypertension. We used the everted duodenal sac to study untreated, orally treated, and parenterally treated groups of SH and WKy rats. In untreated groups, net calcium transport was lower (P less than 0.05) in the SH rat than in the WKy rat (0.46-0.66 vs 0.81-1.04, all data mumole/g segment wet wt per hr). Both groups responded to treatment (SH vs WKy; 0.84-0.90 vs 1.56-1.57, P less than 0.05), but even in treated groups net calcium transport by the SH rat was lower than that by the WKy rat (P less than 0.05). Net water transport increased 3- to 8-fold in response to treatment in the WKy but not in the SH rat. The increased water transport prevented demonstration of treatment-mediated increased calcium transport based on serosal/mucosal concentration ratio in the WKy rat. We conclude that (i) both the SH and the WKy rat have the capability to increase calcium transport when treated with an agonist having vitamin D activity; (ii) the unstimulated and stimulated transport rate is lower in the SH rat than in the WKy rat; and (iii) water transport responds to treatment in the WKy rat but not in the SH rat.

Morphological and functional recovery of rat small intestine following localized hyperthermia.

Structural and functional changes in the rat small intestine following localized hyperthermia were examined. In anaesthetized male Sprague-Dawley rats a 10 cm segment of mid-small intestine was temporarily exteriorized, suspended in a cup containing Krebs-Ringer solution, and either heated at 43.5 degrees C or sham-heated at 38 degrees C for 45 min. The intestinal segments were studied 1, 4, 7, 21 and 42 days later by histopathological examination, determination of wet weight, dry weight and gross segment area, and by measuring absorption of 15 mM D(+)-glucose containing 14C-labelled D(+)-glucose as a tracer. Intestinal glucose transport was assessed by two different techniques: the everted sac method (in vitro) and luminal perfusion-recirculation (in vivo). After 1 day, heated intestinal segments exhibited marked mucosal damage, consisting of loss of epithelial cells and destruction of villi. Re-epithelialization had occurred by day 4, but mucosal architecture remained abnormal throughout the observation period. Hyperthermia caused significant thickening of the intestinal wall: at 4 days the thickening was due to oedema, whereas at 42 days tissue mass per cm2 in heated segments had increased by approximately 53 per cent compared with sham-heated control segments. At 1 day, net glucose transport in vitro in heated segments was reduced to 20 per cent and the serosal/mucosal concentration ratio to 57 per cent of that of control segments. In vivo, glucose transport in heated intestine at 4 days was 45 per cent of that of controls. From 4 days on, glucose transport improved gradually, and at 42 days there was no significant difference between heated and sham-heated animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium transport and vitamin D in three breeds of spontaneously hypertensive rats.

Conflicting results have been published by different laboratories comparing the rate of intestinal calcium transport and concentration of circulating 1,25-dihydroxyvitamin D (1,25-[OH]2D) in the spontaneously hypertensive rat (SHR) and control Wistar-Kyoto rat (WKY): They have been reported to be greater, the same, or lower in the SHR than in the WKY. We tested the possibility that the conflicting results might be breeder-related by measuring 1) the rate of intestinal mucosal calcium transport, 2) the concentration of circulating 25-hydroxyvitamin D (25-OH-D) and 1,25-(OH)2D, and 3) the concentration of intestinal mucosal receptor for 1,25-(OH)2D in the two strains of animals from three different breeders. Sodium and water transport were also measured because of their relevance to hypertension. Blood pressure was always higher and calcium, as well as mean sodium and water transport, was always lower in the SHR than in the WKY. The concentration of 1,25-(OH)2D was the same, higher, or lower in the SHR than in the WKY and was age- and breeder-dependent. Mean mucosal 1,25-(OH)2D receptor concentration was higher in the SHR and was variable, depending on breeder. We conclude that 1) the rate of calcium transport is lower in the SHR than in the WKY and independent of breeder and concentration of 1,25-(OH)2D in serum, 2) the variability in 1,25-(OH)2D concentration among investigators may be breeder-dependent, and 3) the higher receptor concentration in the intestinal mucosa of the SHR could be a compensatory response to the decreased rate of calcium transport. These differences in calcium and sodium transport may be an expression in the enterocyte of factors etiological for hypertension.

Calcium and sodium transport in the duodenum of the Dahl salt sensitive and salt resistant rat.

We measured food intake, body growth and transport of calcium and sodium by duodenum of female Dahl salt sensitive (DS) and salt resistant (DR) rat strains. Food intake and body growth were similar for DS and DR rats taking both 0.4 and 8% sodium chloride diets. Food intake increased with age up to 5 weeks and then remained constant despite continuing body growth. Comparing DS and DR rats fed the 0.4% sodium chloride diet at 6 and 11 weeks or the 8% sodium chloride diet at 6 weeks, transport of calcium and sodium were the same in both the DS and DR groups. Transport of calcium, but not sodium, was lower at 11 than at 6 weeks. Comparing simultaneous feeding of either 0.4 or 8% sodium chloride diets to 6-week old DS and DR rat strains, transport of calcium tended to be lower in animals fed the 8% as compared to the 0.4% sodium chloride diet, and the difference was significant for net 40Ca transport for DR rats. The DS rat fed on 8% sodium chloride had higher systolic blood pressure (SBP) than the DR rat. We conclude that growing DS and DR rats, ingesting equal amounts of food, do not differ in duodenal calcium and sodium transport measured by the everted sac technique. The response to feeding sodium chloride differs between strains: the high salt diet decreases net 40Ca transport in the DR but not the DS strain.

Increased intestinal growth in the streptozotocin-diabetic rat occurs prior to changes in hormone secretion.

Depressed somatic growth in the rat with streptozotocin diabetes is associated with greatly enhanced intestinal growth. In patients with diabetes mellitus, growth hormone is elevated. Therefore, we measured the association between gut growth and serum growth hormone in the streptozotocin-diabetic rat. At 10 days growth hormone did not differ in control, untreated diabetic and insulin-treated diabetic groups. At 20 days of diabetes, growth hormone was elevated in untreated diabetic groups, but depressed to control levels by insulin. Intestinal growth was markedly elevated in all diabetic groups by 10 days, prior to the increases in hormone levels. We conclude that the enhanced intestinal growth in diabetes is probably independent of growth hormone.

Gastrin, somatostatin, and alimentary tract growth responses to small intestinal resection in the rat.

We studied the early time-course of gastrin, somatostatin, and gut growth responses to 70% resection of mid-small intestine. Serum and antral gastrin increased by the 2nd day following resection and remained elevated for the 10-day period of study. Antral somatostatin remained unchanged, suggesting that the increase in gastrin was a selective antral response. Duodenum and ileum showed marked growth stimulation, which was progressive with time, and earlier and greater in duodenum. In contrast, gastric growth was unaffected. Thus, early responses to resection are characterized by specificity of gastrin, somatostatin, and growth effects.

Resection of rat small intestine: calcium, phosphorus, and fat balances and 1,25-dihydroxycholecalciferol.

In rat with massive resection of mid-small intestine, calcium transport per segment, measured by in vivo perfusion 10 days after surgery, is decreased in duodenum and ileum but is the same in cecum and colon as compared with controls with transection and reanastomosis of mid-small intestine. To extend these findings, we measured balances of calcium, phosphorus, and fat from the 5th to 10th day after surgery and serum concentration of 1,25-dihydroxycholecalciferol on the 10th day after surgery in this experimental model. We found steatorrhea in the resected group, but balances of calcium and phosphorus and serum levels of 1,25-dihydroxycholecalciferol were the same in resected and control groups. We conclude that decreased transport defined by direct examination of membrane function may be undetectable when net transport is measured by balance. Calcium balance during early post-resection period provides no evidence for future calcium deficiency in this experimental model.

Intestinal disaccharidase activity following pancreatic duct occlusion in the rat.

The influence of pancreatic secretions on growth and brush-border enzyme activity, throughout the entire small intestine, was examined in the rat. Pancreatic secretions were excluded from the gut lumen by stapling the pancreatic ducts, without interruption of bile flow. The entire small intestine was studied as four segments; the duodenum and three distal segments of equal length. Weight of intestine and mucosa, and mucosal sucrase, isomaltase, lactase, and alkaline phosphatase activity were measured 10-15 days following pancreatic duct occlusion, or sham-operation. The duodenum of pancreatic duct-occluded animals exhibited significant hypertrophy. In general, specific and total disaccharidase activities were greater in duct-occluded animals than in controls throughout the intestine. The increase was more pronounced in distal than in proximal segments. The sucrase/isomaltase ratio was significantly greater in pancreatic duct-occluded animals than in controls in the two distal segments. Alkaline phosphatase activity was not affected by pancreatic duct occlusion. The greater relative increase of disaccharidase activities and sucrase/isomaltase activity ratios in the distal segments of duct-occluded animals, indicates a more important regulatory role of pancreatic enzymes in the distal small intestine. It is concluded that regulation of intestinal brush-border enzyme activity by pancreatic secretion is selective for enzyme and site as follows: disaccharidases, but not alkaline phosphatase, are regulated; the sucrase subunit of the sucrase/isomaltase complex is most sensitive to regulation, while lactase is least sensitive; and the regulatory effect on disaccharidases is greater in distal than in proximal intestine.

Intestinal calcium transport in the spontaneously hypertensive rat: response to calcium depletion.

We previously found intestinal Ca2+ transport to be lower in the spontaneously hypertensive (SH) as compared with the Wistar-Kyoto control (WKY) rat. These animals were fed a relatively high (1%) Ca2+ diet, and the concentration of 1 alpha,25-dihydroxycholecalciferol [1 alpha,25(OH)2D3] in serum was the same in both groups. In the present experiment we tested the possibility that the lower Ca2+ transport in the SH rat was the result of unresponsiveness to 1 alpha,25(OH)2D3. We fed diets high and low in Ca2+ and measured serum 1 alpha,25(OH)2D3 and Ca2+ transport. Serum 1 alpha,25(OH)2D3 increased in response to Ca2+ depletion at both 5 and 12 wk in both the WKY and SH rat. With high-Ca2+ diet, Ca2+ transport was lower in SH than in WKY when studied 1) in vitro in duodenum at 5 wk of age, and 2) in vivo in proximal and distal small intestine at 12 wk of age. Ca2+ transport increased in SH in response to Ca2+ depletion, but not in WKY, except in distal small intestine in vivo at 12 wk. In summary, although Ca2+ transport is lower in the SH as compared with the WKY rat when vitamin D activity is basal through feeding a high-Ca2+ diet, Ca2+ transport increases in the SH rat in response to the increase in 1 alpha,25(OH)2D3 produced by feeding a low-Ca2+ diet. We conclude that 1) the vitamin D-regulated component of mediated Ca2+ transport is intact in the SH rat and is unrelated to hypertension, and 2) mediated Ca2+ transport under basal conditions, i.e., nonvitamin D-regulated, differs in the SH and WKY rats and may be related to hypertension.

Measurement of alpha-glucosidase activity in serum from patients with cystic fibrosis or pancreatitis.

We measured the activity of a non-lysosomal alpha-glucosidase with pH optimum near 6.0 in serum from a wide variety of patients, using the fluorogenic substrate, 4-methylumbelliferyl-alpha-D-glucopyranoside. Acutely ill patients with cystic fibrosis (CF) demonstrated significant increases in alpha-glucosidase compared with CF outpatients. The former group of CF patients experienced far more severe chronic pulmonary disease than did the latter, whereas both groups had similar degrees of gastrointestinal impairment. Patients with pancreatitis associated with trauma or complicated by severe necrosis, hemorrhage, or abscess also displayed greater increases in alpha-glucosidase than did patients with uncomplicated (edematous) pancreatitis. For CF outpatients and patients with either edematous pancreatitis or pancreatic cancer, the alpha-glucosidase activity was similar to that for the general hospital-patient population. Corresponding changes were not observed for other measured serum glycosidases (alpha-fucosidase, alpha-mannosidase, beta-glucuronidase, beta-N-acetylglucosaminidase). Measurement of serum alpha-glucosidase may be of value in assessing the clinical course in CF and in differentiating necrotizing from edematous pancreatitis.