Biomedical subjects

A Metcalf

Publications and source records attributed to A Metcalf.

6 recordsLinked to original sources

PubMed1995

Anorectal disorders. Five common causes of pain, itching, and bleeding.

Hemorrhoids are a common source of anorectal symptoms, which are determined by their size. A helpful measure in small hemorrhoids is a high-fiber diet; in moderate lesions, ligature therapy is effective. Surgery should be reserved for large hemorrhoids. Anal fissures, probably caused by trauma to the anal canal during defecation, may persist because of a cycle of hard stools, pain, and reflex spasm. A high-fiber diet and sitz baths relieve acute fissures. Lateral partial internal sphincterotomy is usually effective when they become chronic. Perianal abscess is often caused by acute infection of the anal glands; fistula is the result of chronic infection. Swelling and induration may be present. Pain is throbbing and continuous, and perianal examination may require use of an anesthetic. Incision and drainage with follow-up to ensure resolution of infection is required. Pruritus ani may result from several contributing conditions or may be idiopathic. Restoration of dry, intact perianal skin is the treatment goal. Patients should be taught gentle hygiene and drying methods and advised to avoid caffeine or other dietary items that seem to exacerbate symptoms. Condylomata acuminata cause bleeding and pain if allowed to progress. Biopsy should be considered in patients at risk of dysplasia. Repeated application of caustic topical agents may help small lesions. Large, extensive, and persistent lesions require surgical ablation.

Abscess↗

PubMed1994

Misoprostol is effective treatment for patients with severe chronic constipation.

To assess the efficacy of misoprostol in the treatment of patients with severe chronic constipation, nine such patients were enrolled in a double-blind, randomized, crossover study of misoprostol (1200 micrograms/day) or placebo, that lasted three weeks. During this period each patient received the drug for one week and placebo for another with a week washout period in between. A colonic transit study, using radiopaque markers, was performed during each of the treatment weeks, while the number of stools and their total weight was recorded by each patient for the appropriate periods. Colonic transit time was significantly and consistently decreased by misoprostol compared to placebo [66 hr +/- 10.2 vs 109.4 hr +/- 8.1 (P = 0.0005)]. Misoprostol significantly increased the total stool weight per week [976.5 g +/- 288.8 vs 434.6 g +/- 190.5 (P = 0.001)] and also significantly increased the number of stools per week compared to placebo [6.5 +/- 1.3 vs 2.5 +/- 0.11 (P = 0.01)]. The incidence of abdominal pain was similar in both groups. We concluded that misoprostol, during a short trial period, proved effective in increasing the frequency and weight of bowel movements and decreasing colonic transit time in patients with severe chronic constipation. It may be used as a therapeutic measure to treat such patients.

Adult↗

PubMed1993

Synaptic vesicle proteins and early endosomes in cultured hippocampal neurons: differential effects of Brefeldin A in axon and dendrites.

The pathways of synaptic vesicle (SV) biogenesis and recycling are still poorly understood. We have studied the effects of Brefeldin A (BFA) on the distribution of several SV membrane proteins (synaptophysin, synaptotagmin, synaptobrevin, p29, SV2 and rab3A) and on endosomal markers to investigate the relationship between SVs and the membranes with which they interact in cultured hippocampal neurons developing in isolation. In these neurons, SV proteins are detected as punctate immunoreactivity that is concentrated in axons but is also present in perikarya and dendrites. In the same neurons, the transferrin receptor, a well established marker of early endosomes, is selectively concentrated in perikarya and dendrites. In the perikaryal-dendritic region, BFA induced a dramatic tubulation of transferrin receptors as well as a cotubulation of the bulk of synaptophysin. Synaptotagmin, synaptobrevin, p29 and SV2 immunoreactivities retained a primarily punctate distribution. No tubulation of rab3A was observed. In axons, BFA did not produce any obvious alteration of the distribution of SV proteins, nor of peroxidase- or Lucifer yellow-labeled early endosomes. The selective effect of BFA on dendritic membranes suggests the existence of functional differences between the endocytic systems in dendrites and axons. Cotubulation of transferrin receptors and synaptophysin in the perikaryal-dendritic region is consistent with a functional interconnection between the traffic of SV proteins and early endosomes. The heterogeneous effects of BFA on SV proteins in this cell region indicates that SV proteins are differentially sorted upon exit from the TGN and are coassembled into SVs at the cell periphery.

Amino Acid Sequence↗

PubMed1993

Collagenous colitis associated with chronic constipation.

We present a case in which the classical histopathologic features associated with collagenous colitis were present throughout the colectomy specimen of a 69-year-old woman operated on for life-long intractable idiopathic constipation. This patient had never suffered from episodes of watery diarrhea. The reasons for this paradox are unclear, but suggest that a thickened collagen table and damaged surface epithelium may not be entirely specific pathologic findings marking the clinicopathological syndrome of collagenous colitis.

Aged↗

PubMed1992

Ca2+ stores in Purkinje neurons: endoplasmic reticulum subcompartments demonstrated by the heterogeneous distribution of the InsP3 receptor, Ca(2+)-ATPase, and calsequestrin.

The nature of second messenger-responsive intracellular Ca2+ stores in neurons remains open for discussion. Here, we demonstrate the existence in Purkinje cells (PCs) of endoplastic reticulum (ER) subcompartments characterized by an uneven distribution of three proteins involved in Ca2+ storage and release: the inositol 1,4,5-trisphosphate (InsP3) receptor, Ca(2+)-ATPase, and calsequestrin. Ca(2+)-ATPase and the InsP3 receptor have a widespread, although not identical, distribution throughout the ER. Calsequestrin is localized throughout the smooth ER and is particularly concentrated in pleiomorphic vesicles with a moderately electron-dense core, which appear to represent a subcompartment of the smooth ER. In double-labeling experiments many of these vesicles were unlabeled by InsP3 receptor antibodies. These results suggest a key role of the ER as an intracellular Ca2+ store and demonstrate a possible structural basis for distinct intracellular Ca2+ pools regulated by different second messengers.

Animals↗

PubMed1985

Pregnancy following ileal pouch-anal anastomosis.

Of 92 women undergoing proctocolectomy with ileal "J" pouch-anal anastomosis, between January 1981 and May 1983, six have successfully conceived and carried a pregnancy to term. Three patients had transient deterioration of anorectal function during the third trimester of pregnancy which resolved after delivery. Four patients delivered vaginally without perceptible alteration in subsequent continence. Ileal pouch-anal anastomosis is compatible with normal childbearing postoperatively. The route of delivery should be individualized in these patients.

Adult↗