Biomedical subjects

F M Perkins

Publications and source records attributed to F M Perkins.

24 records · Page 2Linked to original sources

PubMed1981

Epithelial organization and hormone sensitivity of toad urinary bladder cells in culture.

Two continuous cell lines (TB-M and TB-6c) derived from epithelial cells of the toad urinary bladder form epithelia in culture that manifest hormone-sensitive transepithelial transport. Development of transepithelial electrical resistance (R) and transport rate (ISC) are dependent on time and density of cells seeded, but steady-state ISC and R are characteristic for each cell line and independent of seeding density. Some responses of intact toad bladder are preserved in culture, whereas others are altered or absent. Neither cell line responds to vasopressin. Analogues of cAMP increase sodium transport and urea permeability in both cell lines but do not affect water permeability. The intramembrane particle aggregates associated with the vasopressin- and cAMP-induced increase in water permeability of the intact bladder could not be detected in the cell lines. Aldosterone increases sodium transport in both cell lines, and the time course and concentration dependence of the response to aldosterone are similar to those of the intact bladder. The relative effect of a series of steroids on ISC reveals corticosterone to be a more potent mineralocorticoid in cultured cells than in the intact bladder.

Animals↗

PubMed1980

Studies of renal cell function using cell culture techniques.

Cell culture, a powerful tool for the study of cell biology, offers advantages for the study of renal cell function. Epithelial cells derived from a variety of organs, including the kidney, form oriented epithelial sheets in culture that have many structural characteristics (microvilli, tight junctions) of epithelia in situ. There is evidence of transepithelial transport of salt and water by cells of two lines (MDCK and LLC-PK1) derived from mammalian kidney. LLC-PK1 cells may also manifest the glucose transport system of the proximal tubule. Cells of both lines have adenylate cyclase activity sensitive to hormones. Two lines of cells derived from toad urinary bladder form epithelia with a high transepithelial resistance and transport sodium actively from apical to basolateral surface. The rate of sodium transport in both lines is stimulated by cyclic AMP and by aldosterone. There are important differences in the characteristics of the response of the two lines to aldosterone as well as in their sensitivity to inhibition of sodium transport by amiloride. These differences may lead to new insights regarding the molecular events in the response to aldosterone and in the inhibitory action of amiloride. Cultures of kidney cells have also been used effectively to study the biosynthesis of the hormonal derivative of vitamin D and to study prostaglandin production. In addition, cell culture is ideally suited for study of the developmental biology of the kidney.

Aldosterone↗

PubMed1977

In vitro inhibition of rho-aminohippurate transport by halogenated anesthetics.

The effects of four commonly used halogenated anesthetic agents (methoxyflurane, halothane, enflurane and fluroxene) on rho-aminohippurate (PAH) uptake by rabbit renal cortical slices were examined. All agents depressed PAH uptake in a linear dose-dependent manner after 60 minutes of incubation and the effect was reversible. When the data were normalized for anesthetic potency, all agents exhibited a parallel dose-response curve. Since these agents do not share a common metabolite, it is concluded that the depression of PAH transport is mediated primarily by a direct effect of the agents acting through a common pathway. Exposure of kidney slices to perithreshold concentrations of halothane and enflurane for 180 minutes did not result in a cumulative inhibitory effect on PAH transport. A slight time-dependent effect was seen with methoxyflurane. It is suggested that with prolonged exposure metabolic conversion of methoxyflurane may occur leading to further inhibition of PAH uptake.

Aminohippuric Acids↗

PubMedDate not supplied

New technique for superior hypogastric plexus block.

BACKGROUND AND OBJECTIVES: : The classical technique for blocking the superior hypogastric plexus (SHP) described by Plancarte sometimes renders the desired needle placement difficult. This article describes an alternative approach for blocking the SHP. METHODS: Three patients with pelvic pain from endometriosis underwent an anterior approach to block the SHP with fluoroscopic guidance. The ages of the patients ranged from 21 to 34 years, pain duration ranged from 2 to 4 years, and pain score on a visual analog scale of 0-10 ranged from 7 to 8. RESULTS: All patients had significant pain relief immediately after the block. The pain scores postblock ranged from 0 to 4/10. The duration of pain relief varied from 1 to 14 days. The contrast material localized at the L5 vertebral body in the posteroanterior and lateral views. CONCLUSION: We present a new approach to block the SHP with fluoroscopic guidance in patients with chronic benign pelvic pain.

Adult↗

PubMedDate not supplied

Effects of gabapentin in acute inflammatory pain in humans.

BACKGROUND AND OBJECTIVES: The aim of the study was to examine the analgesic effects of the anticonvulsant, gabapentin, in a validated model of acute inflammatory pain. METHODS: Twenty-two volunteers were investigated in a double-blind, randomized, placebo-controlled cross-over study. Gabapentin 1,200 mg or placebo was given on 2 separate study days. Three hours after drug administration, a first-degree burn injury was produced on the medial aspect of the nondominant calf (12.5 cm(2), 47 degrees C for 7 minutes). Quantitative sensory testing (QST) included pain ratings to thermal and mechanical stimuli (visual analog scale [VAS]), assessments of thermal and mechanical detection thresholds, and areas of secondary hyperalgesia. Side effects drowsiness and postural instability were assessed by subjective ratings (VAS). RESULTS: The burn injury induced significant primary and secondary hyperalgesia (P <.0001). Gabapentin diminished the decrease in mechanical pain threshold in the burn area (P =.04) and reduced secondary hyperalgesia, but the reduction was not significant (P =.06). Heat pain thresholds, pain during the burn, and mechanical pain in the area of secondary hyperalgesia were not significantly changed by gabapentin (P <.2). Ratings of drowsiness and unsteadiness during walking were significantly higher for gabapentin than for placebo (P <.05). CONCLUSIONS: The study indicates that gabapentin has no analgesic effect in normal skin, but may reduce primary mechanical allodynia in acute inflammation following a thermal injury. These observations suggest a clinical potential of gabapentin in the treatment of postoperative pain.

Acetates↗

PubMedDate not supplied

Oral anticoagulant prophylaxis and epidural catheter removal.

BACKGROUND AND OBJECTIVES: The use of regional anesthesia in patients receiving anticoagulants is controversial. The purpose of this review is to document the incidence of neurologic complications with insertion and removal of an epidural catheter in patients receiving oral anticoagulants and antiplatelet medication. METHODS: A retrospective review was made of the charts of 459 patients who underwent hip pinning or hip or knee replacement under regional anesthesia and received postoperative epidural analgesia and warfarin thromboembolism prophylaxis. The number of patients receiving preoperative antiplatelet therapy and warfarin, as well as baseline coagulation parameters, was documented. For patients who had postoperative epidural analgesia, the prothrombin time on the day of epidural catheter removal was obtained. Neurologic complications during the hospital stay were noted. RESULTS: Spinal anesthesia was administered to 47 patients and epidural anesthesia and postoperative analgesia to 412. Before surgery, antiplatelet therapy was given to 270 and warfarin to 180 patients, with some patients receiving both. The mean +/- SD preoperative prothrombin and partial thromboplastin times were 10.8 +/- 1.2 seconds (normal, 9.6-11.1 seconds) and 27.5 +/- 3.5 seconds (normal, 24.6-33.2 seconds), respectively. Blood on needle or catheter insertion was noted in 21 patients, all of whom were taking antiplatelet medication and/or warfarin. Epidural catheters remained postoperatively for a mean of 43.6 +/- 12.5 hours (range 5-118 hours). The mean prothrombin time on the day of epidural catheter removal was 14.1 +/- 3.2 seconds. Four postoperative peripheral neuropathies were detected. There was no clinical evidence of spinal hematoma in any patient. CONCLUSIONS: Epidural catheter placement and removal in patients taking oral anticoagulants appears to be safe. Careful monitoring of the patient for evidence of spinal hematoma after epidural catheter removal is recommended.

Administration, Oral↗