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Biomedical subjects

M L Allen

Publications and source records attributed to M L Allen.

At least 55 records · Page 3Linked to original sources
PubMed1990

The effect of raw onions on acid reflux and reflux symptoms.

Patients with gastroesophageal reflux often describe heartburn after "spicy meals." One ingredient common to most such meals is onion. We investigated the effects of onion on acid reflux and reflux symptoms in 16 normal subjects and 16 heartburn subjects. Subjects were studied with an esophageal pH probe for 2 h after the ingestion of a plain hamburger and a glass of ice water. The identical meal, with the addition of a slice of onion, was ingested on a counterbalanced day. Variables measured were number of reflux episodes, percentage of the time pH was less than four, heartburn episodes, and belches. Ingestion of onions did not increase any of the reflux variables measured in normals. However, onions significantly increased all measures in heartburn subjects, compared with the no-onion condition, and compared with normals under the onion condition. Onions can be a potent and long-lasting refluxogenic agent in heartburn patients.

Adult↗
PubMed1989

The biosynthesis and actions of prostaglandins in the renal collecting tubule and thick ascending limb.

PGE2 formed by renal collecting tubules is an important factor in regulating NaCl and water reabsorption in the collecting tubule and medullary thick ascending limb. PGE2 appears to act, depending on its ambient concentration, via several different receptors present in these renal epithelia to modulate cAMP turnover in both positive and negative directions. These putative PGE receptors form a family of receptors, all coupled to G proteins, and this family of PGE receptors is homologous to the adrenergic receptor family.

Animals↗
PubMed1989

Subcutaneous tunneled intrapleural catheters in the long-term relief of right upper quadrant pain of malignant origin.

A 33-yr-old, 42-kg female, with extensive hepatic metastatic disease with intractable pain unresponsive to narcotic analgesics, nonsteroidal antiinflammatory drugs, and tricyclic antidepressants, is presented. Management of this patient's intractable pain with local anesthetics administered via a tunneled intrapleural catheter is discussed. Tunneling techniques are described. The patient continued to experience excellent pain relief at 6 wk follow-up.

Adult↗
PubMed1989

Regulation of cAMP metabolism by PGE2 in cortical and medullary thick ascending limb of Henle's loop.

We have examined the regulation by prostaglandin E2 (PGE2) of hormone-induced adenosine 3',5'-cyclic monophosphate (cAMP) accumulation in cells isolated by immunodissection from both the medullary and cortical thick ascending limb of Henle's loop of rabbit kidney. At concentrations greater than 10(-8) M, PGE2, but not sulprostone (16-phenoxy-17,18,19,20-tetranor-PGE2 methylsulfonilamide), caused cAMP accumulation in both cortical and medullary thick limb cells. However, at concentrations of less than or equal to 10(-8) M, both PGE2 and sulprostone inhibited arginine vasopressin (AVP)-, calcitonin-, and glucagon-induced cAMP accumulation in medullary thick ascending limb (mTAL) cells. In cortical thick limb (cTAL) cells, sulprostone also inhibited AVP-, calcitonin-, and parathyroid hormone (PTH)-induced cAMP accumulation. The inhibitory effects of PGE2 and of sulprostone were blocked by pretreatment of mTAL and cTAL cells with pertussis toxin. Membranes prepared from mTAL cells exhibited a [3H]PGE2 binding activity that was stimulated on addition of the stable guanosine 5'-triphosphate (GTP) analogue, 5'-guanosine gamma-thiotriphosphate (GTP gamma S); moreover, sulprostone inhibited [3H]PGE2 binding. Our results suggest that PGE2 can function via a prostaglandin E receptor linked to a guanine nucleotide regulatory protein, Gi, to attenuate hormone-induced cAMP formation in both mTAL and cTAL cells of rabbit kidney.

Animals↗
PubMed1989

Lower esophageal sphincter pressure, esophageal body motor functioning, and esophageal acid sensitivity.

Esophageal acid sensitivity is believed to develop as a result of esophageal acid exposure, contributing factors being gastroesophageal reflux and delayed esophageal acid clearance. The relationship among lower esophageal sphincter pressure, motor functioning of the body of the esophagus, and esophageal acid sensitivity was examined by comparing the results from 912 patients and normal subjects studied with both esophageal manometric and Bernstein acid infusion tests. Positive acid infusions were statistically more closely associated with hypotensive lower esophageal sphincter pressures than with any motor abnormality in the body of the esophagus. Of the several esophageal body motor abnormalities considered, only feeble peristalsis had significantly more positive Bernstein tests than did normal esophageal body motor functioning. The findings from this study demonstrate that hypotensive lower esophageal sphincter pressure is more closely associated with an acid-sensitive esophagus than is impaired esophageal body motor functioning.

Esophagitis↗
PubMed1988

Mitogenic signaling pathways regulating expression of c-myc and ornithine decarboxylase genes in bovine T-lymphocytes.

Expression of the c-myc and ornithine decarboxylase (ODC) genes is elevated early after mitogenic activation of T-lymphocytes, and regulation of the two genes seems to be coupled to transmembrane signaling pathways that are in part different. The evidence is consistent with protein kinase C (PKC) being both necessary and sufficient to induce expression of the ODC gene in response to treatment of T-cells with either the mitogen concanavalin A (Con A) or biologically active phorbol esters. Furthermore, there seems to be no involvement of events dependent on calmodulin (CaM) in the regulation of ODC in these cells. The situation with c-myc is more complex. In contrast to ODC, transcription of this gene is not stimulated by treatment of resting T-cells with phorbol esters alone, but the cells respond to phorbol esters in combination with the calcium ionophore ionomycin. Induction of the c-myc gene by Con A is inhibited by CaM antagonists. These results are consistent with a model in which transcriptional activation of the c-myc gene in resting T-lymphocytes requires two signals, one from PKC and the other involving CaM.

Animals↗
PubMed1988

Episodic twice-daily treatment for recurrent genital herpes.

A new dosage regimen of orally administered acyclovir, 800 mg twice daily for five days, for the treatment of recurrent genital herpes was compared with the standard dosage of 200 mg given five times per day. A double-blind study of 157 patients was used to evaluate the safety and efficacy of both regimens. The new regimen was well tolerated, more convenient, and as effective as the standard dosage. In male patients, the new regimen may be more effective than the standard regimen of 200 mg given five times per day to treat lesions that are already present.

Acyclovir↗
PubMed1988

Anorectal functioning in fecal incontinence.

Manometric testing was performed on three groups of subjects: 14 patients complaining of fecal incontinence, 14 age- and sex-matched continent patients, and 14 sex-matched younger normal controls. The younger group displayed significantly stronger contractions of the external anal sphincter and puborectalis than the two patient groups, which did not differ. No differences were found in the relaxation of the internal and sphincter. The incontinent group required a significantly larger stimulus in order to detect rectal distension compared to either the continent patients or the younger normals. An additional group of unmatched normals and incontinent patients demonstrated significant differences in their ability to retain rectally infused saline. The patients leaked sooner and retained less; however, the performance of the normals was considerably reduced from that reported in previous studies. The aging process seems to result in weakening of the striated muscles of the anal canal, although fecal incontinence need not occur. The afferent limb of the anorectal sensorimotor mechanism does not necessarily deteriorate with aging. A lower threshold for sensation of rectal distension among continent individuals apparently helps them to avoid incontinent episodes, even though maximum contractile pressures in their anal canal are no different from a comparable group of incontinent individuals.

Adult↗
PubMed1988

Water swallows versus food ingestion as manometric tests for esophageal dysfunction.

Data from 100 consecutive patients with chest pain or dysphagia, or both, who underwent esophageal testing with standard water swallows and upright food ingestion were retrospectively evaluated. In addition to having manometric patterns monitored, patients were asked to relate symptoms during testing. Of 77 patients with a history of dysphagia, significantly more had abnormal manometry during the test meal than with water swallows (79 vs. 43%, p less than 0.005). Additionally, dysphagia, although reported in only 8% of these patients during standard testing, occurred in 47% during the test meal (p less than 0.001). Of 60 patients with chest pain, symptoms were rarely reported (5%) with water or with food ingestion. We conclude that manometry with food ingestion should be used as a provocative test in anatomically normal patients with dysphagia.

Adult↗
PubMed1988

Immunodissection of cortical and medullary thick ascending limb cells from rabbit kidney.

A procedure was developed for isolating thick ascending limb cells from either the outer medulla or the inner cortex from rabbit kidneys. Dispersed cells derived from the medulla or cortex were incubated with goat anti-human uromucoid (Tamm-Horsfall glycoprotein) serum, washed, and applied to culture dishes coated with affinity-purified anti-goat immunoglobulin G. Nonadherent cells were removed by washing. Routinely, 10(6) or 7 X 10(4) adherent cells were obtained per gram of rabbit outer medulla or inner cortex, respectively. Greater than 97% of the adherent cells stained for Tamm-Horsfall antigen, and examination of freshly isolated cells by transmission electron microscopy established that they had morphological properties expected for thick limb cells. Freshly isolated medullary thick limb (MTALH) cells consistently accumulated cAMP in response to arginine vasopressin (AVP), thyrocalcitonin, prostaglandin E2 (PGE2), and glucagon. PGE2, thyrocalcitonin, parathyroid hormone, and AVP, but not isoproterenol or glucagon, reproducibly stimulated cAMP accumulation in freshly isolated cortical thick limb (CTALH) cells. MTALH cells produced immunoreactive PGE2 when incubated with 10 microM arachidonic acid. In summary, large numbers of highly purified and hormonally responsive rabbit MTALH and CTALH cells can be obtained by immunodissection using commercially available antibody preparations. Because the Tamm-Horsfall antigen is present as an extracellular determinant on thick ascending limb epithelia from many species, this general approach likely can be used to isolate CTALH and MTALH cells from most mammalian kidneys.

Animals↗
PubMed1988

Biliopleural fistula as a complication of percutaneous biliary drainage: experimental evidence for pleural inflammation.

We describe 3 patients in whom biliopleural fistulae complicated percutaneous biliary drainage. All patients had complete obstruction of their biliary tree because of malignancy. Biliopleural fistulae developed as a complication of inadvertent catheter removal in 2 patients and of catheter dysfunction in the third. Early reinstitution of biliary drainage and successful drainage of the pleural space led to complete recovery in all patients. An animal model to evaluate the effects of bile in the pleural space in normal rabbits revealed rapid absorption of bilirubin, the production of a polymorphonuclear-predominant exudative effusion with extremely high LDH levels, and resolution with a macrophage influx. We conclude that biliopleural fistulae are heterogeneous in their presentation, depending upon the persistence of biliary drainage into the pleural space, the volume of exudative effusion, and the presence of suppurative complications.

Aged↗
PubMed1988

Validation of an ambulatory esophageal pH monitoring system.

The present study documents the accuracy of a commercially available ambulatory esophageal pH instrument. The distal esophagus of five subjects with daily heartburn was monitored for 24 h in the laboratory via an antimony pH electrode. The computer output from the ambulatory unit was compared to the on-line recording in terms of all events in which the pH dropped below four. A signal detection model was used, with an on-line pH tracing serving as the criterion response. The events noted as true positives (80%) were an accurate representation by the computer output of the events of pH less than four displayed by the on-line recording. The processing done by this particular ambulatory system tends to actually "ignore" transient pH drops (18% false negatives) and, may, in fact, provide more physiologically meaningful information than hardwired analog techniques for 24-h pH monitoring. The results confirm that ambulatory pH monitoring can produce meaningful and reliable physiological data concerning gastroesophageal reflux.

Adult↗
PubMed1987

Effect of BMY-28100, a new cephalosporin, on Staphylococcus aureus nasal carriage.

In order to examine the in vivo activity of BMY-28100, serial quantitative nasal cultures were taken from 52 nasal carriers of Staphylococcus aureus following administration of the antimicrobial. Nasal carriage rates and mean log titers decreased significantly during (days 2-4 and 5-8) and following (days 1-2 and 6-7) treatment. No change in antibiotic sensitivities was noted in follow-up isolates, and the MIC90 remained at 2mcg/ml. BMY-28100 demonstrated good in vivo activity against Staphylococcus aureus.

Adult↗