Nucleoside transport in human colonic epithelial cell lines: evidence for two Na+-independent transport systems in T84 and Caco-2 cells

RT-PCR of RNA isolated from monolayers of the human colonic epithelial cell lines T84 and Caco-2 demonstrated the presence of mRNA for the two cloned Na+-independent equilibrative nucleoside transporters, ENT1 and ENT2, but not for the cloned Na+-dependent concentrative nucleoside transporters, CNT1 and CNT2. Uptake of [3H]uridine by cell monolayers in balanced Na+-containing and Na+-free media confirmed the presence of only Na+-independent nucleoside transport mechanisms. This uptake was decreased by 70-75% in the presence of 1 microM nitrobenzylthioinosine, a concentration that completely inhibits ENT1, and was completely blocked by the addition of 10 microM dipyridamole, a concentration that inhibits both ENT1 and ENT2. These findings indicate the presence in T84 and Caco-2 cells of two functional Na+-independent equilibrative nucleoside transporters, ENT1 and ENT2.

Synthesis of cytokinin glucuronides for the selection of transgenic plant cells

Glucuronide derivatives of cytokinins have been synthesized for use as agents for the selection of plant cells transformed with a beta-glucuronidase (GUS) gene. In this selection system, the GUS gene functions as both a selectable, as well as a screenable gene. GUS liberates active cytokinin from inactive cytokinin glucuronides which then stimulates growth and regeneration of the transformed cells. The frequently used cytokinin N6-benzyladenine was conjugated to glucuronic acid at N-3 or at N-9 but only the former was a substrate for GUS. The glucuronide of isopentenyladenine was also made, by coupling at the N-3. This compound was readily hydrolysed by GUS.

Effect of exercise training on dyspnea measures in patients with chronic obstructive pulmonary disease

PURPOSE

This study investigated the possible mechanisms for the expected improvement in dyspnea with pulmonary rehabilitation.

METHODS

Lung function, clinical ratings of dyspnea, and exercise responses were studied in 44 patients with chronic obstructive pulmonary disease who participated in an outpatient program consisting of 1.5 hours per week of supervised education, breathing training, and upper/lower extremity exercise.

RESULTS

After rehabilitation, there were significant increases in forced expiratory volume in 1 second (FEV1, 7%; P = .02), maximal inspiratory mouth pressure (PImax, 17%; P < .001), and the transition dyspnea index focal score (3.4; P < .001) and a significant decrease in the slope of dyspnea/power (0.12 versus 0.09; P = .001) during exercise. Patients who demonstrated > or = 0 mL of change in FEV1 or > or = 5 cm H2O of change in PImax exhibited significant decreases in the slopes for dyspnea/power.

CONCLUSIONS

After pulmonary rehabilitation, there was a significant improvement in dyspnea. Although there was no evidence of a physiologic training response or enhanced mechanical efficiency, the modest increase in FEV1 and the increase in respiratory muscle strength appeared to contribute to the reduction in dyspnea.

Absorption pharmacokinetics of atenolol in patients with the Marfan syndrome

The negative inotropic and chronotropic effects of beta-blocker therapy have been reported to reduce morbidity and mortality in patients with Marfan syndrome; however, little is known about the pharmacokinetics of atenolol after oral administration of multiple doses to patients with the Marfan syndrome. We studied the pharmacokinetics of atenolol in 13 such patients aged 18.7 +/- 2.9 years who were receiving 1.78 +/- 0.58 mg/kg/day (70.1 +/- 20.3 mg/m2/day) of atenolol for 6 weeks or longer. Mean +/- SD percentage change in baseline heart rate after the administration of atenolol was -18.03 +/- 16.59% and mean +/- SD percentage change in exercise heart rate after atenolol was -33.22 +/- 14.75% (P < .01). Six to 8 atenolol serum concentrations were collected in each patient during a 12-hour dosing interval and were determined by high-performance liquid chromatography with ultraviolet detection. Serum atenolol concentrations at 0 (123 +/- 70 micrograms/L) and 12 (116 +/- 66 micrograms/L) hours were within 20% of each other and were thus assumed to be at steady-state. A one-compartment, steady-state pharmacokinetic model with first-order absorption and elimination was fitted to the concentration-time data for each patient using nonlinear regression. Maximal concentration was 343 +/- 120 micrograms/L, and the mean half-life was 4.72 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Partial typhlectomy and ileocolostomy for treatment of nonreducible cecocolic intussusception in a horse

Cecocolic intussusception was detected in a 2-year-old male Standardbred horse with a 3-day history of signs of intermittent colic. The entire cecum, which was located within the lumen of the right ventral colon, was edematous and necrotic, and could not be manually reduced. A colotomy was made, and partial typhlectomy was performed. An ileocolostomy also was performed. To prevent eversion of the cecal base, the site of invagination into the colon was oversewn. Several postoperative complications were treated, including peritonitis, thrombophlebitis, anemia, and hypoproteinemia, and 1 year after surgery, the horse was healthy and in training.

Evaluation of abomasal outflow diversion as an experimental model of hypochloremic, hypokalemic metabolic alkalosis in lactating cows

Four adult, lactating dairy cows were subjected to diversion (loss) of gastric contents through a T-shaped cannula placed in the cranial part of the duodenum just distal to the pylorus. Diversion was continued for 10 to 12 hours, at which point the cows were very weak and depressed. The volume of effluent during this period ranged from 37.3 to 46.8 L, with the largest volume being produced during the first four hours. All cows became dehydrated, with mean packed cell volume and total plasma protein concentration increasing 30% and 19.6%, respectively, but with only a slight increase in plasma creatinine concentration. Plasma Cl- concentrations decreased from a mean of 97.3 mEq/L at the beginning of diversion to a mean of 87.2 mEq/L at eight hours. This was followed by a plateau or slight increase in concentrations over the final hours of diversion. Plasma K+ concentration followed a similar pattern, decreasing from a mean of 3.9 mEq/L to a mean of 2.94 mEq/L at six hours, followed by increasing values until termination of diversion. No changes in plasma Na+ concentration were noted, except for a mild decrease in one cow. Plasma calcium concentrations decreased significantly, reaching 6.6 +/- 0.6 mEq/L at the end of diversion. Venous pH, plasma HCO3- concentration, and plasma base excess concentration increased during the first four to eight hours of diversion, followed by a gradual decline. Although a mild hypochloremic metabolic alkalosis resulted from diversion of abomasal outflow in all cows, substantiated by a mild increase in plasma strong ion difference, the changes observed were not as great as expected.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of 0.9, 3.6, and 7.2% NaCl for correction of experimentally induced hypochloremic, hypokalemic metabolic alkalosis in sheep

Nine adult female sheep were each surgically fitted with an Ivan and Johnston reentrant cannula in the cranial part of the duodenum just distal to the pylorus. By diversion (loss) of abomasal outflow, this model has been shown to consistently induce hypochloremic, hypokalemic metabolic alkalosis, accompanied by hyponatremia and dehydration. Each sheep was subjected to 3 treatment trials, each preceded by a 24-hour prediversion period, and a diversion period during which a syndrome of hypochloremia (68 +/- 2 mEq/L), hypokalemia, hyponatremia, and metabolic alkalosis was induced. Development of this syndrome was attributable to losses of large amounts of acid and electrolytes in the abomasal effluent. Mean total electrolyte contents of the effluent were: Cl-, 650 +/- 27 mEq; Na+, 388 +/- 23 mEq; and K+, 123 +/- 12 mEq, with total volume loss ranging from 3.6 to 10.0 L of gastric contents and pH ranging from 3 to 5. Decreases in plasma electrolyte concentrations also can be attributed to decreased intake, because anorexia developed shortly after the onset of diversion. Electrolyte losses in urine during diversion were minimal for Cl- (mean +/- SEM, 12.0 +/- 5.1 mEq), but were greater for Na+ (124.2 +/- 14.5 mEq) and K+ (185.1 +/- 31.2 mEq). Treatments consisted of 0.9% NaCl (300 mosm/L), 3.6% NaCl (1,200 mosm/L), and 7.2% NaCl (2,400 mosm/L) administered over a 2-hour period, with the administered volume determined by the estimated total extracellular fluid Cl- deficit. Significant difference was not found among treatments, with all solutions resulting in return of clinicopathologic and physical variables to prediversion values within 12 hours of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Repair of sacral fracture in two dairy cattle

Sacral fractures in 2 dairy cattle were repaired surgically for cosmetic reasons. A heifer had a Salter-Harris type-I fracture of the fifth sacral vertebra, which was repaired with a 4.5-mm narrow dynamic compression plate. A cow had complete fracture of the fourth sacral body, which was repaired with 2 extra-large plastic spinous process plates. Both fixations were successful in restoring the dorsal contour of the sacrococcygeal region.

Chronic frontal sinusitis in dairy cattle: 12 cases (1978-1989)

Chronic frontal sinusitis in 12 dairy cattle most often was associated with a history of dehorning, in which the sinus was entered (67%), or with respiratory tract disease (25%). The most common organisms isolated were Actinomyces pyogenes and Pasteurella multocida. Signs of infection did not develop for months in some cattle and were often intermittent. The most common clinical signs included anorexia, lethargy, fever, frontal bone distortion, exophthalmos, abnormal posture, nasal discharge, and neurologic abnormalities. Treatment consisted of trephination at 2 sites, drainage and lavage of the sinus cavity, and administration of antibiotics and analgesics. Eight cattle responded well to treatment and were discharged, but 4 others had signs of CNS involvement and died or were euthanatized. Trephination of the frontal sinus cavity at carefully chosen sites and antibiotic treatment are indicated when sinusitis is suspected. Drainage of the sinus cavity is imperative to avoid extension of the infection into the CNS.

Sperm microinjection twins: deoxyribonucleic acid fingerprinting

The twins described are clearly nonidentical. The DNA fingerprints obtained show that they are the children of the putative mother and father, indicating the success of the microinjection procedure.

Medullary thyroid carcinoma: Australian experience with genetic testing

Linkage analysis has been performed in four pedigrees with multiple endocrine neoplasia type 2A (MEN 2A) or familial medullary thyroid carcinoma (MTC) using pericentromeric chromosome 10 probes. Important information regarding carrier status has been provided in 10 individuals, many of whom would not have been identified by pentagastrin stimulation testing. We have also used pulsed field gel electrophoresis (PFGE) to link the probes H4.IRBP and pMCK2 to a 150 kb fragment. Using PFGE, no evidence was found in DNA from lymphocytes of a major DNA rearrangement in two individuals affected with MEN 2A and an individual with MEN 2B compared with normals. Metastatic MTC from one patient has been used to generate a cDNA library which will be used to screen for candidate MEN 2A and MEN 2B gene(s).

Alteration of morphogenesis by the v-myc oncogene in transplants of mammary gland

To see if individual oncogenes can alter three-dimensional growth in vivo, we have inserted the v-myc oncogene into transplants of mouse mammary gland. Primary cultures of mammary epithelial cells were infected with helper-free retrovirus to insert v-myc oncogenes, and transplanted into cleared mammary fat pads (mammary glands from which the natural epithelium had been removed) of host mice. Uninfected transplants, and transplants infected with retrovirus constructs that carry no oncogene, grew to form an epithelial 'tree' resembling normal mammary gland, as expected. Transplants infected with retroviruses carrying v-myc oncogenes grew to form a characteristic, abnormal (hyperplastic) pattern in which the ducts were more densely packed than normal. Integration of the retrovirus in the transplants was demonstrated. The effect of the oncogene was local, not systemic, as some transplants showed adjacent areas of normal and hyperplastic growth. Thus v-myc can alter morphogenesis without growth becoming disorganized.

Cardiovascular responses to rowing

The purpose of this investigation was to evaluate the cardiovascular responses to rowing. In the first part of the study, heart rate (HR) and cardiac output (Q) were measured at rest and at three steady-state exercise levels on the variable-resistance rowing ergometer in 10 female and 11 male subjects. Q was determined non-invasively by the equilibration method of CO2 re-breathing, and stroke volume (SV) was calculated. Subjects varied in rowing ability from healthy, inexperienced rowers to competitive athletes. The linear relationships between Q and oxygen consumption for the women (r = 0.57; P less than 0.001; slope = 5.2 +/- 1.1) (mean +/- SD) and the men (r = 0.58; P less than 0.001; slope = 6.1 +/- 1.4) were similar to published values for other types of upright exercises. For both mean and women, SV increased from rest to the first level of exercise, and then reached a plateau at or before the second exercise intensity. Between the second and third levels of exercise, SV decreased significantly in the female subjects (107 +/- 18 vs 94 +/- 16 ml; P less than 0.05), but not in the male subjects (128 +/- 1 1 vs 126 +/- 15 ml; P = not statistically significant). In the second part of the study, HR, Q, and SV were compared on the cycle and rowing ergometers on successive days in eight additional subjects. At similar levels of oxygen consumption and Q, HR was significantly higher, and SV was significantly lower during rowing exercise than with cycle exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Narcotic and other drug use: a spectrum

Zinberg and Lewis foresaw developments in the substance abuse field in particular and in human services in general with the development of a "Spectrum of a Difficult Medical Problem." We believe this spectrum has far reaching implications and value for researchers, theoreticians, planners and practitioners currently in the substance abuse field both in conceptualizing drug involvement with its diversity of potential concerns, as well as planning treatment for drug involved clients. The application of a spectrum need not be limited to the category of drugs known as narcotics; this concept can also be applied to involvement with drugs from other categories, e.g., stimulants, sedative/hypnotics, hallucinogens, etc.

Optic array determinants of apparent distance and size in pictures

This study explored whether special mechanisms are operative in picture perception to correct for the distortion that occurs when pictures are viewed from the wrong station point. Five photographs were taken of a layout composed of two same-sized dolls positioned at different distances on a flat untextured ground. Perspective differences existed between the photographs as a function of varying the distance of the camera to the layout. Each picture was viewed from five station points along the normal by 12 adults who estimated the relative magnitude of the depth interval between the dolls and judged whether the rear doll was objectively smaller, larger, or the same size as the front doll. No evidence was found of a compensation mechanism operating to stabilize the pictured layout. Distance and size judgments were affected in a manner that was consistent with what would occur if an actual layout and the conditions under which it were viewed were similarly transformed.

Optic array determinants of apparent distance and size in pictures

This study explored whether special mechanisms are operative in picture perception to correct for the distortion that occurs when pictures are viewed from the wrong station point. Five photographs were taken of a layout composed of two same-sized dolls positioned at different distances on a flat untextured ground. Perspective differences existed between the photographs as a function of varying the distance of the camera to the layout. Each picture was viewed from five station points along the normal by 12 adults who estimated the relative magnitude of the depth interval between the dolls and judged whether the rear doll was objectively smaller, larger, or the same size as the front doll. No evidence was found of a compensation mechanism operating to stabilize the pictured layout. Distance and size judgments were affected in a manner that was consistent with what would occur if an actual layout and the conditions under which it were viewed were similarly transformed.

The presence of type III collagen in the developing tooth

Type I and type III collagens have been isolated from dental papilla and dental pulp of bovine tissues by enzymic digestion with pepsin and differential salt precipitation. Type III collagen was further purified by molecular sieve and ion-exchange chromatography. The relative proportions of type III and type I collagens were estimated by two different techniques, gel electrophoresis in the presence of mercaptoethanol, and direct estimation of the alpha1(III)CB3 peptide. Both techniques gave similar values. Type III collagen constituted 24% of papilla and 28% of pulp collagen by the first procedure, and 20% and 31% by the second. 18% of dental follicle collagen was type III.