Biomedical subjects

M K Barry

Publications and source records attributed to M K Barry.

At least 19 recordsLinked to original sources

PubMed1999

A peritrophin-like protein expressed in the embryonic tracheae of Drosophila melanogaster.

We have cloned and sequenced a cDNA from Drosophila melanogaster that encodes a protein homologous to the peritrophins, a family of chitin-binding proteins from the peritrophic matrix of insects. Unexpectedly, the gene, Gasp, is expressed in the embryonic tracheae. We suggest that this family of proteins may be present in other tissues than the peritrophic matrix, particularly where nutrient or gas exchange are important, and/or where invasion by parasites or viruses is possible. We have also mapped two similar genes that had been sequenced by the Berkeley Drosophila Genome Project, and find that these three very similar genes are not clustered, but are located on three different chromosomes.

Amino Acid Sequence↗

PubMed1999

Defunctioning loop ileostomy: a prospective audit.

BACKGROUND: Defunctioning loop ileostomies are uncommonly used forms of fecal diversion. The aim of this study was to determine the morbidity associated with both construction and reversal of loop ileostomies. STUDY DESIGN: An analysis was performed of all patients who underwent loop ileostomy construction or reversal between 1990 and 1997, with data being collected prospectively. RESULTS: One-hundred-two patients, (43 male, 59 female) with a mean age of 38 years (range 13 to 81 years) had loop ileostomies constructed. Indications for ileostomy construction included inflammatory bowel disease (76 patients), ultralow anterior resection for carcinoma (16 patients), or miscellaneous reasons (10 patients). Nine patients (9%) had complications arising from ileostomy construction including 4 parastomal infections, 3 high output ileostomies, 1 small-bowel obstruction, and 1 ileostomy stenosis in the early postoperative period. Only the stricture required surgical intervention. All other complications improved with conservative management. Mean time to ileostomy reversal was 120 days. Three patients (4%) had complications associated with reversal. All of these complications required surgical intervention, 2 for small bowel obstruction, and 1 for small bowel perforation. Currently 84 patients have had their ileostomy reversed, and 12 patients have had their loop ileostomy converted to a permanent stoma for reasons not related to the loop ileostomy itself. CONCLUSIONS: Defunctioning loop ileostomy is associated with low morbidity. We recommend a defunctioning ileostomy as the procedure of choice for temporary fecal diversion.

Adolescent↗

PubMed1999

Pancreas regeneration after resection: does it occur in humans?

Although pancreatic regeneration after partial resection or pancreatic injury (restitutio ad integrum) has been demonstrated in animal models, whether regeneration occurs in the human pancreas is unknown. Our aim was to determine whether the human pancreas regenerates after subtotal resection. We reviewed pre- and postoperative computerized tomograms (CTs) of 21 patients after proximal pancreatectomy (50-60% resection) for malignancy with no recurrent disease during follow-up of pancreatic parenchymal abnormalities. Three fixed anatomic measurements (pancreatic body width, tail width, and length) were compared with the same region 10 and 21 months after surgery. Data are expressed as mean +/- SEM. Pancreatic measurements before and 10 months after resection did not differ for body width (2.0+/-0.1 cm vs. 1.8+/-0.1 cm), tail width (2.2+/-0.2 cm vs. 1.8+/-0.2 cm) or length (8.2+/-0.3 vs. 7.4+/-0.4 cm) (p> or =0.1 each). At 21 months after resection, measurements were less for body width and tail width (2.2+/-0.2 cm vs. 1.5+/-0.2 cm and 2.2+/-0.1 cm vs. 1.5+/-0.2 cm, respectively; p = 0.01) and unchanged for length (8.1+/-0.4 cm vs. 8.1+/-0.4 cm; p = 0.9). We conclude that the human pancreas does not regenerate after partial anatomic (50%) resection.

Adult↗

PubMed1998

Surgical management of intrahepatic cholangiocarcinoma: a 31-year experience.

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignant primary tumor of the liver. It is, though, a rare tumor and little is known regarding its natural history, clinicopathologic characteristics, or the outcomes of surgical therapy. We reviewed the experience of 61 patients with ICC seen by the surgical service at the Mayo Clinic over a 31-year period. Patient demographic and clinical data were recorded, as were survival statistics. Pathologic data were also obtained and patients stratified according to the TNM classification. Twenty-eight patients were resected for cure. Overall, 45 patients died of ICC. Of the patients resected for cure, survival at 3 years was 60%. No pathologic condition was found to be associated with the development of ICC. Overall survival correlated with stage of the tumor. Among patients resected for cure, stage did not correlate with survival. Prognosis for patients with ICC remains poor; resection, though, appears to prolong survival.

Adult↗

PubMed1998

Can adrenal incidentalomas be safely observed?

We currently recommend excision of adrenal incidentalomas > or = 4 cm in size and all hormonally active tumors. The optimal management and follow-up of smaller nonfunctioning tumors are controversial. The aim of this study was to determine the clinical outcome of a well defined population of patients with incidentalomas followed without operative intervention. The study group comprised 231 patients, identified from the records of abdominal or thoracic computed tomographic (CT) scans performed between 1985 and 1989. The primary outcome variable analyzed was survival. Follow-up was obtained by office records, telephone contact, or letter. There were 101 male and 130 female patients with a mean age at diagnosis of 64 years (range 5-86 years). Most adrenal tumors were unilateral (right 113; left 98); 20 were bilateral. Mean tumor size was 2 cm (range 1-6 cm). In nine (4%) patients the tumor was > or = 4 cm. Follow-up [mean 7 years; range 1 month (patient died) to 11.7 years] was complete in 224 (97%) patients. Ninety-one (39%) patients had one or more additional CT scans performed during the follow-up period, with only four patients demonstrating a > 1 cm increase in the size of the adrenal mass. Surgical excision of these four lesions identified benign pathology. Eighty-one (35%) patients died of conditions unrelated to adrenal pathology. No patient developed subsequent adrenal hyperfunction or adrenal malignancy. Within the context of our guidelines, conservative management of adrenal incidentalomas considered benign or nonfunctioning at diagnosis is appropriate. Additional information provided by repeat CT scanning appears to confer limited benefit. This study does not support laparoscopic removal of small, nonfunctional adrenal tumors, as has been suggested.

Adolescent↗

PubMed1998

Transabdominal preperitoneal laparoscopic inguinal herniorrhaphy: assessment of initial experience.

OBJECTIVE: To evaluate our initial experience with laparoscopic inguinal herniorrhaphy. DESIGN: We retrospectively studied a consecutive series of patients selectively chosen for laparoscopic repair of inguinal hernia. MATERIAL AND METHODS: The study cohort consisted of 173 patients treated by a single surgeon between 1992 and 1995. For all operations, a transabdominal approach was used. Follow-up was obtained by telephone contact or letter. RESULTS: The study group consisted of 167 male and 6 female patients with a mean age at operation of 55 years (range, 15 to 81). During the study period, 206 laparoscopic inguinal hernia repairs were performed in the 173 patients. Only one patient (0.6%) required conversion to laparotomy. Bilateral hernia repair was done in 31 patients (18%). Of the 206 procedures, 63 repairs (31%) were performed for recurrent hernias. In 69% of the patients, the procedure was completed on an outpatient basis. Early postoperative complications necessitating surgical intervention occurred in four patients. The median time to return to work or normal physical activity was 7 days for unilateral and 12 days for bilateral hernia repair (P = 0.18). A mean follow-up of 29 months was obtained for 171 patients (99%). In six patients (3%), a recurrent hernia developed. Four of these six patients had previously undergone an open surgical procedure on the side of the recurrence. CONCLUSION: Laparoscopic inguinal herniorrhaphy is a feasible alternative to open hernia repair. This operation, however, should be reserved for selected patients. Longer follow-up and controlled trials comparing laparoscopic and tension-free open herniorrhaphy are necessary for assessment of the relative benefits of this procedure.

Adolescent↗

PubMed1997

Is familial hyperparathyroidism a unique disease?

BACKGROUND: Familial hyperparathyroidism is a rare condition reported to behave more aggressively than sporadic hyperparathyroidism. METHODS: A retrospective (1975 to 1995) analysis was performed on 30 such patients. All patients had at least one first-degree relative with surgically treated hyperparathyroidism and no personal or family history of multiple endocrine neoplasia. RESULTS: There were 19 women and 11 men with a mean age of 39 years (range, 13 to 78 years). Fourteen patients (47%) had nephrolithiasis. The mean serum calcium level was 11.6 mg/dl (range, 10.5 to 15.3 mg/dl). Twenty-three primary and 15 repeat explorations (eight recurrent and seven persistent disease) were performed during the study period. Follow-up was obtained on all patients and ranged from 1 to 21 years (mean, 12 years). At the conclusion of the study, hypercalcemia (five recurrent and one persistent) was present in six patients (20%). CONCLUSIONS: Familial hyperparathyroidism is a distinct and unique entity. Patients are diagnosed at a young age and have a high incidence of nephrolithiasis. Long-term follow-up is mandatory because of the high incidence of both recurrent and persistent hyperparathyroidism. Surgical treatment should include subtotal parathyroidectomy and routine transcervical thymectomy performed in centers with experience in the management of multiple-gland parathyroid disease.

Adolescent↗

PubMed1997

Audit of colorectal cancer surgery by non-specialist surgeons.

BACKGROUND: Some authorities recommend that colorectal cancer should be treated in specialist units but evidence that non-specialist units demonstrate comparatively poor results may be lacking. METHODS: Between 1987 and 1991, 267 patients were operated on by four general surgeons, none of whom was a specialist in colorectal surgery. Procedure-related complications, postoperative mortality and disease-related survival rates were analysed. RESULTS: There were four cases of intraperitoneal sepsis (1 per cent) and five of 189 patients (3 per cent) had clinical anastomotic dehiscence; there was no case of wound dehiscence. The postoperative mortality rate after elective and emergency surgery was 2 and 13 per cent respectively. The 5-year disease-related survival rate for curative and palliative surgery was 67 and 9 per cent respectively. There were no significant differences between the surgeons. CONCLUSION: Disease-related variables such as early-stage disease and fewer patients presenting as emergencies may have a greater favourable influence on ultimate survival than surgeon-related variables.

Aged↗

PubMed1996

Methods of renal blood flow measurement.

Variations in regional renal blood flow have been implicated in a variety of disease states. Many techniques have been developed in an attempt to accurately assess these changes. The microsphere technique is the most widely used method at the present time. This technique allows focal measurements to be performed, but there is a conflict between the resolution of the method and the number of microspheres necessary in each sample. New imaging techniques such as tomography and autoradiography enable visual assessment of renal blood flow. Though there is no ideal method, these techniques have opened up new possibilities in the quantification of regional renal blood flow.

Autoradiography↗

PubMed1996

Laparoscopic oophorectomy: a prospective evaluation in pre-menopausal breast cancer with particular reference to incidence and severity of menopausal symptoms.

Laparoscopic oophorectomy offers potential advantages over other methods of ovarian ablation. In this prospective study the technique, complications and side-effects have been assessed in 69 consecutive patients. Menopausal symptoms were assessed using two scoring systems - the Kupperman index and the Women's Health Questionnaire. The serum beta oestradiol levels fell rapidly post-operatively (from 540 pmol/l to 25 pmol/l within 1 month). Menopausal symptoms were mild in 75% of patients and severe in none. Complications occurred in three patients. Laparoscopic oophorectomy has an important role to play in the management of pre-menopausal breast cancer and this study confirms that is well tolerated and gives good short-term results.

Adult↗

PubMed1995

Neural mechanisms in basal and meal-stimulated ileal absorption.

The ingestion of a meal stimulates absorption from the jejunal lumen and is dependent on intact neural pathways. Few studies of ileal absorptive responses to a meal have been performed. This study tested two hypotheses: (1) a meal stimulates ileal glucose, water, and ion absorption, and (2) intact intestinal neurotransmission is necessary to maintain the basal and meal-stimulated absorptive states in the ileum. Absorption studies (n = 50) using 14C-labeled PEG were performed on six dogs with 25-cm ileal Thiry-Vella fistulas (TVF). Four groups were randomly studied over 4 hr. Intraluminal oxethazaine (2 mg/dl) was administered to the TVF in Groups 2 and 4 after the 1st hour to produce neural blockade. A control volume of water was administered to the TVF in Groups 1 and 3 after the 1st hour. A 480 kcal meal was ingested at the end of the 2nd hour in groups 3 and 4. Ileal water, ion, and glucose absorption were increased significantly (P < 0.05) by the ingestion of a meal. TVF oxethazaine significantly reduced (P < 0.05) basal water and ion absorption but had no effect on meal-stimulated absorption. Ileal absorption of water, ions, and glucose is significantly increased by the ingestion of a meal. Basal ileal absorption appears to be partly dependent upon intact neurotransmission. Postprandial ileal absorption appears to be independent of neural blockade, implicating circulating hormones, paracrine mediators, or neurotransmission within the myenteric plexus of the enteric nervous system as the primary modulators of meal-stimulated ileal absorption.

Absorption↗

PubMed1995

Cholinergic agents modulate transport in the isolated, perfused ileum.

The mammalian small intestine is extensively innervated by cholinergic nerve fibers, including projections to the muscular and submucosal layers. This study tested the hypothesis that cholinergic agents modulate ileal transport independent of alterations in intestinal vascular resistance and motility. Ten-centimeter segments of rabbit ileum (n = 32) were vascularly perfused ex vivo with a physiologic electrolyte solution containing red cells. The lumen was perfused with an electrolyte solution containing [14C]polyethylene glycol. Net fluxes of water, sodium, and chloride were calculated during three 20-min periods: basal, drug infusion, and recovery. Agents infused at a final arterial concentration of 10(-5) mole/liter included acetylcholine, atropine, and hexamethonium. Measured perfusion pressure reflected changes in vascular resistance. Recovery calculations controlled for motility effects. Acetylcholine caused significant secretion of water, sodium, and chloride (P < 0.05). The infusion of atropine or hexamethonium alone had no effect. Atropine but not hexamethonium prevented the prosecretory effect of acetylcholine. There were no significant changes in perfusion pressure or 14C recovery for any infused agent. Acetylcholine-induced ileal secretion is (1) mediated via atropine-sensitive muscarinic cholinergic receptors, (2) independent of extraintestinal neural pathways, and (3) independent of changes in vascular resistance or motility. These data support the hypothesis that acetylcholine influences ileal transport directly, independent of alterations in vascular resistance and motility.

Acetylcholine↗

PubMed1995

Luminal dopamine modulates canine ileal water and electrolyte transport.

Previous studies have suggested that dopamine stimulates active ileal ion absorption via alpha 2-adrenergic or dopaminergic receptor activation. Identification of a dopamine 1a receptor on rat enterocytes located in intestinal crypts prompted this investigation of the effect of luminally administered dopamine on water and ion transport in the canine ileum. Absorption studies (n = 27) were performed in dogs with 25-cm ileal Thiry-Vella fistulas. Perfusion with [14C] PEG was used to calculate absorption of water and electrolytes from the Thiry-Vella fistula. Experiments consisted of three 1-hr periods: basal, luminal drug infusion at 10(-4) M, and recovery. Agonists used included dopamine (DOP: alpha-adrenergic, D1 and D2 receptor) and SKF 38393 (D1 receptor). Antagonists used included terazosin (TZ: alpha 1) and yohimbine (YOH: alpha 2). DOP caused significant increases in water and electrolyte absorption. TZ and YOH prevented the dopamine-induced proabsorptive response. Luminal DOP may serve as a proabsorptive modulator of ileal transport, acting via alpha 1, alpha 2, and dopaminergic receptors. The development of more potent proabsorptive dopamine analogs, which maintain the ability to broadly activate mucosal receptors, may be useful in such clinical situations as diabetic diarrhea, short gut syndrome, or following small bowel transplantation.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1995

A prospective study of acid reflux and globus pharyngeus using a modified symptom index.

Previous authors have demonstrated an association between gastro-oesophageal reflux and globus pharyngeus. With the advent of 24-h pH monitoring the strength of this association has been questioned. A prospective study was performed using a 'Symptom Index' of acid reflux. A positive result was recorded when one out of two globus sensations occurred with acid reflux. The symptom index was assessed prospectively in 21 patients with a history of globus pharyngeus. In eight patients with significant acid reflux as defined by standard pH criteria the symptom index was positive in all cases. The remaining 13 patients had no objective evidence of significant reflux and the symptom index was negative. The symptom index is a useful additional marker to determine the significance of acid reflux in the pathogenesis of globus pharyngeus.

Adult↗

PubMed1994

Effect of alpha 1-adrenergic blockade on canine ileal water, electrolyte, and glucose absorption.

Meal ingestion stimulates an increase in small intestinal water and electrolyte absorption. Endogenous norepinephrine may at least partially mediate this meal-stimulated proabsorptive response. Luminally administered alpha 1-adrenergic agonists such as norepinephrine and phenylephrine cause significant small bowel absorption, which can be prevented by the selective alpha 1-adrenergic antagonist terazosin. This study tested two hypotheses: (1) a meal stimulates ileal water, electrolyte, and glucose absorption; and (2) meal-stimulated ileal absorption is mediated via alpha 1-adrenergic receptor activation. Absorption studies (N = 27) were performed on dogs with 25-cm ileal Thirty-Vella fistulas (TVF). Perfusion with [14C]PEG was used to calculate absorption of water, electrolytes, and glucose from the TVF. Three groups were randomly studied over 4 hr: (1) terazosin alone, (2) meal alone, and (3) terazosin plus meal. Terazosin (10(-4) M) was administered to the TVF in groups 1 and 3 following the first hour. A 480-kcal mixed canine meal was ingested at the end of the second hour in groups 2 and 3. Ileal water, electrolyte, and glucose absorption increased significantly in response to meal ingestion (P < 0.05). Luminal terazosin did not significantly alter basal or meal-stimulated ileal absorption. In conclusion, meal ingestion stimulates ileal absorption of water, electrolytes, and glucose. Neither basal nor meal-stimulated ileal absorption is altered by alpha 1-adrenergic receptor blockade. These data suggest that nonadrenergic neural pathways or humoral factors are the likely mediators of meal-induced intestinal absorption.

Adrenergic alpha-Antagonists↗

PubMed1994

Luminal adrenergic agents modulate ileal transport: discrimination between alpha 1 and alpha 2 receptors.

Luminal alpha-adrenergic agonists alter ileal water, ion, and glucose transport by a local mechanism. This study tested the hypothesis that luminal adrenergic agents modulate ileal transport selectively, via specific alpha 1 and alpha 2 receptors. Absorption studies (n = 72) were performed on dogs with 25-cm ileal Thiry-Vella fistulas (TVF). Perfusion with (14C) polyethylene glycol was used to calculate absorption of water, ions, and glucose from the TVF. Experiments included four 1-hour periods. Agonists used were phenylephrine (alpha 1), clonidine (alpha 2), and norepinephrine (alpha 1 > alpha 2 and beta). Antagonists used were terazosin (alpha 1) and yohimbine (alpha 2). Phenylephrine and norepinephrine caused significant increases in water and ion absorption (p < 0.05). Clonidine caused significant decreases in water, ion, and glucose absorption (p < 0.05). Terazosin and yohimbine had no effect alone. Terazosin prevented the proabsorptive effect of phenylephrine and norepinephrine, and yohimbine blocked the prosecretory effect of clonidine. Yohimbine significantly increased the norepinephrine-induced proabsorptive effect. Luminal alpha-adrenergic agents selectively modulate ileal transport. Alpha 1-receptor activation causes a proabsorptive response, whereas alpha 2-receptor activation causes a prosecretory response. The combination of a luminally administered mixed alpha- and beta-adrenergic agonist (norepinephrine) with alpha 2 receptor blockade (yohimbine) may prove useful in pathologic secretory states such as intestinal transplants, diabetic diarrhea, or diarrhea-associated endocrinopathies.

Adrenergic alpha-Agonists↗

PubMed1994

Nitric oxide modulates water and electrolyte transport in the ileum.

OBJECTIVE: To test the hypothesis that nitric oxide is a modulator of ileal water and ion transport. SUMMARY BACKGROUND DATA: Nitric oxide is produced in the vascular endothelium and enteric neural plexuses of the intestine and is involved in gastrointestinal motility and smooth muscle contractility. Little is known about the role of nitric oxide in intestinal epithelial transport. METHODS: Ten-centimeter rabbit ileal segments (n = 50) were vascularly perfused with an electrolyte solution containing red cells. The lumen was perfused with a solution containing 14C-PEG. Net fluxes of water and ions were calculated during three 20-minute periods: basal, drug infusion, and recovery. Perfusion pressure was recorded to document changes in vascular resistance. Agents infused included the nitric oxide synthase substrate L-arginine, the nitric oxide source sodium nitroprusside, the substrate control D-arginine, and the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester. RESULTS: L-arginine and sodium nitroprusside caused absorption of water and ions. NG-nitro-L-arginine methyl ester caused secretion of water and ions, which was prevented by synchronous infusion of L-arginine. Infusion of D-arginine had no effect. Both L-arginine and sodium nitroprusside caused mild vasodilation. CONCLUSIONS: Inhibition of endogenous nitric oxide synthesis by NG-nitro-L-arginine methyl ester causes secretion of water and ions. This secretion is reversed by administration of the nitric oxide synthase substrate L-arginine. These findings are consistent with the hypothesis that endogenous nitric oxide has a proabsorptive influence over the ileum in the basal state.

Absorption↗

PubMed1993

Luminal adrenergic agonists modulate ileal transport by a local mechanism.

Intestinal transport is controlled by neural pathways, hormones, and luminal agents. Luminal adrenergic agents influence water and ion transport in the jejunum. This study tested two hypotheses: (i) luminal adrenergic agents influence ileal water, ion and glucose transport, and (ii) luminal adrenergic agents exert their effects locally and selectively. Absorption studies (n = 46) were performed on dogs with two adjacent 25-cm ileal Thiry-Vella fistulas (TVF). Perfusion with [14C]polyethylene glycol was used to calculate absorption of water, ions, and glucose from the distal TVF. Experiments were composed of three 1-hr periods: basal, luminal adrenergic agonist infusion, and recovery. In group 1 the adrenergic agonists were administered to the distal TVF: norepinephrine (alpha 1 > alpha 2 and beta), phenylephrine (alpha 1), clonidine (alpha 2), and isoproterenol (beta). In group 2 the adrenergic agonists were administered to the proximal TVF, with absorption measured in the distal TVF. In group 1 norepinephrine and phenylephrine caused a significant increase in water absorption (P < 0.05). Clonidine and isoproterenol caused decreased absorption of water and ions, with clonidine causing significantly decreased absorption (P < 0.05) of water, ions, and glucose. In group 2 there were no changes in distal TVF absorption. Luminal adrenergic agents did not alter the heart rate in either group. Luminal adrenergic agonists modulate ileal transport via a local mechanism. A proabsorptive response is observed with alpha 1 agonists, while alpha 2 and beta agonists cause a prosecretory effect. Inhibition of glucose absorption appears to be selectively mediated via the alpha 2-adrenergic receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗