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Biomedical subjects

R B Wait

Publications and source records attributed to R B Wait.

At least 55 records · Page 3Linked to original sources

Verapamil attenuates stress-induced gastric ulceration.

Since many of the proposed etiologic factors leading to gastric stress ulceration involve stimulation of calcium influx, the effect of verapamil, a potent calcium channel blocker, on the gastric mucosa in cold-restrained inbred rats was assessed. Twenty-nine rats received intraperitoneal normal saline (2 ml) while the experimental group (N = 29) received 1 mg/kg verapamil in an equal volume of normal saline intraperitoneally. All animals were then stressed at 4 degrees C for 4 hr and sacrificed. Gastrin and fatty acid levels were measured and blinded ulcer scoring of the gastric mucosa was carried out. Verapamil-treated animals had decreased frequency and severity of gastric stress ulceration as assessed by ulcer index, ulcer grade, and number of ulcers/animal. In addition, the plasma gastrin levels tended to be lower in the verapamil group. Fatty acid levels were similarly depressed following cold restraint in both groups. Pretreatment with verapamil significantly decreased gastric ulcerative response to cold-restraint stress in the rat. This effect of verapamil pretreatment may be secondary to cytoprotection of the gastric mucosa, preservation of gastric mucosal blood flow, or blockade of calcium-mediated ulcerogenic stimuli.

Animals↗

Verapamil inhibition of lymphocyte proliferation and function in vitro.

Calcium is a divalent cation which acts both as a cofactor for critical protein function and as a "second signal" to trigger cytosol events after membrane depolarization. The presence of calcium is critical to T-lymphocyte function. Verapamil is a calcium channel blocker at the membrane level and may affect cytosol calcium-calmodulin as well. Verapamil effect was measured on two assays of lymphocyte proliferation (concanavalin A and phytohemagglutinin lectin and alloantigen stimulated) and on cell-mediated cytotoxicity. Verapamil inhibited proliferation at 10(-5) M doses and abrogated it at 10(-4) M. Verapamil interferes with critical calcium-mediated events in T lymphocyte proliferation and function. T-lymphocyte calcium channel blockade may be an effective immunosuppressive strategy.

Animals↗

A curriculum for adolescent mothers: an evaluation.

One hundred and four indigent, pregnant adolescents were selected to evaluate the effect of a prenatal education curriculum presented in a maternity clinic. Adolescent mothers were visited 6 months postpartum to test which short-term, intermediate, and long-term curriculum content items were accurately and effectively retained. Success of the curriculum was evaluated by a trained social worker in the girls' home to ascertain how these content areas were reflected in the adolescent mother's behavior. Short-term matter-child health-care compliance content showed a high degree of success. Intermediate child-rearing content techniques often did not lead to appropriate behavior six months after the baby was born. Long-term educational and vocational performance content did not demonstrate effective long-term retention. Technical aspects of child-rearing, even when deliberately presented by health educators, did not appear to be easily applied in the extended family setting, and long-term goals seemed inconsistent with the adolescent's behavior.

Adolescent↗

Verapamil inhibition of the intestinal effects of substance P.

The undecapeptide substance P (SP) is contained in enterochromaffin cells and circulates in high concentrations in patients with carcinoid syndrome. We have previously reported that elevated SP levels, simulating those reported in patients with carcinoid syndrome, induce profound changes in intestinal water and electrolyte secretion, motility, and blood flow in a canine model. The purpose of this study was to attempt to block the effects of circulating carcinoid levels of SP on intestinal secretion and motility with the calcium channel blocker verapamil. In five dogs a chronic proximal jejunal Thiry-Vella loop was constructed, and after a 2-week recovery the loops were perfused with an isotonic test solution containing 14C-polyethylene glycol as a volume marker. Motor activity was measured by changes in intraluminal pressure and a motility index was calculated with computer-assisted planimetry and expressed as square millimeters per 5 minutes. After a 30-minute baseline period, SP was infused at 50 ng/kg/min for 90 minutes. SP circulating levels rose from a baseline of 6.2 +/- 1.3 pg/ml to a peak of 93.3 +/- 3.1 pg/ml during this infusion. Thirty minutes after the start of this SP infusion, a simultaneous infusion of verapamil (5.0 micrograms/kg/min) was begun at a separate site. During SP infusion there was a significant secretory response of water (-48 +/- 12 microliters/min), Na+ (-7.7 +/- 2.5 microEq/min), Cl- (-8.8 +/- 2.7 microEq/min) and K+ (-0.57 +/- 0.14 microEq/min), and hypermotility (motility index: 1479 +/- 138 mm2/5 min). When verapamil was added a reversal of secretion to net absorption was observed (water: + 116.9 +/- 15.6 microliter/min; Na+: + 13.8 +/- 2.1 microEq/min; Cl-: + 5.5 +/- 2 microEq/min; K+: + 0.38 +/- 0.9 microEq/min) (p less than 0.05). In addition, there was a reduction in motility (motility index: 853 +/- 92 mm2/5 min; p less than 0.05). These results confirm that SP has profound effects on both intestinal motility and secretion and that calcium channel blockade reduces these effects significantly.

Animals↗

Urinary tract infection during pregnancy. Asymptomatic bacteriuria, acute cystitis, and acute pyelonephritis.

Urinary tract infection is one of the most common medical complications of pregnancy, occurring in roughly 10% of all pregnancies. The clinical entities most commonly seen are bacteriuria, acute cystitis, and acute pyelonephritis. Relative stasis of urine due to pregnancy-induced changes in the urinary tract is a significant causative factor. Escherichia coli is the most common responsible organism. Patients with untreated or inadequately treated asymptomatic bacteriuria are at high risk for development of acute pyelonephritis, a serious febrile illness that can lead to major maternal and fetal complications. Patients with acute pyelonephritis should be hospitalized and treated aggressively.

Acute Disease↗

Beneficial effects of verapamil on postischemic renal failure.

The effects of calcium blockade with verapamil on postischemic renal failure were tested in dogs. Two experiments were performed. In experiment 1 (n = 7), one kidney in each dog received an infusion of verapamil and the other received saline for 30 minutes prior to induction of 1 hour of ischemia. Inulin clearance (CIN), urine flow, and renal blood flow (RBF) were measured. Infusion of verapamil increased urine flow from 0.99 to 4.29 ml/min (P less than 0.001). CIN and RBF did not change significantly nor did urine flow in the saline-treated kidney. Three hours after ischemia there was no significant difference in CIN, although it was lower in verapamil-treated kidneys. RBF declined in both treatments. In experiment 2 (n = 6) kidneys were treated with verapamil and saline for 50 minutes beginning immediately after 1 hour of ischemia. Urine flow and CIN were significantly higher in verapamil-treated kidneys during the infusion (3.09 +/- 0.44 versus 0.26 +/- 0.12 ml/min, P less than 0.001; 28.6 +/- 7 .4 versus 6.2 +/- 3.1 ml/min, P less than 0.025, respectively). CIN remained elevated in verapamil-treated kidneys at 3 hours, however RBF was depressed in both verapamil- and saline-treated kidneys. These results suggest that verapamil is a potent diuretic and that verapamil can be given after renal ischemia with significant attenuation of postischemic renal failure.

Acute Kidney Injury↗

Follow-up of methadone-treated and untreated narcotic-dependent women and their infants: health, developmental, and social implications.

This study compares the first year's health, neurodevelopmental status, and environment of infants of drug-dependent mothers attending methadone programs during pregnancy with those of drug-dependent mothers not enrolled in treatment programs (untreated). Both groups were also compared with drug-free controls. During pregnancy, the use of heroin and other psychoactive drugs was common among patients using methadone. Neonatal abstinence syndrome was of longest duration in the methadone group. Infants of both drug groups were smaller at birth, had more neonatal infections, and were viewed as more difficult to care for after nursery discharge than were those of drug-free mothers. On follow-up, mean developmental scores were within the normal range for all groups. The untreated drug-dependent group was more hypertonic than the methadone group, and a high rate of transient or minor motor disturbances and poor attention span was found in both drug groups. The behavior of methadone-treated women during pregnancy and the postnatal period closely resembled that of drug-free controls, and contrasted with untreated drug-dependent women. Methadone-treated women had a high degree of compliance with antepartum care, and 80% continued in the role of parent through the first year. Further investigation will determine whether the consistency of parenting will continue and whether it will enhance the development of their children.

Adult↗

Amniocentesis.

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Amniocentesis↗