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Biomedical subjects

J P Christie

Publications and source records attributed to J P Christie.

At least 19 recordsLinked to original sources
PubMed1998

Alteration of the circadian rhythm of intact parathyroid hormone and serum phosphate in women with established postmenopausal osteoporosis.

Several studies have established that the circulating concentration of intact parathyroid hormone, PTH (1-84), over 24 h follows a circadian rhythm. The importance of this circadian rhythm is not known although some authors have detected alterations in the rhythm in metabolic bone disease and following dietary manipulation. We have studied the circadian rhythm of PTH (1-84) in 8 premenopausal women, 8 postmenopausal women with established osteoporosis and 8 postmenopausal women with no evidence of osteoporosis. Blood samples were obtained at 30-min intervals over a 24-h period and significant differences were found in the profiles of PTH (1-84) and serum phosphate in the three groups studied. Premenopausal women possessed a nocturnal/early morning increase in PTH (1-84) and phosphate (between 2200 and 0700 hours), as did postmenopausal women without osteoporosis. In postmenopausal women with osteoporosis the nocturnal increase in PTH (1-84) and serum phosphate was absent and PTH (1-84) decreased during the period 2200-0700 hours. A shift in acrophase is observed between premenopausal and postmenopausal women without osteoporosis. No acrophase was found in postmenopausal women with osteoporosis for either PTH (1-84) or serum phosphate. No circadian rhythm, acrophase or significant amplitude was observed in serum adjusted calcium or ionized calcium in any group studied. Alterations in the circadian rhythms for PTH (1-84) and serum phosphate occur in patients with postmenopausal osteoporosis that suggest that normal dynamics of PTH (1-84) secretion may play a role in both calcium and phosphate metabolism and the bone remodelling process. Whether these changes are causative or a response to the pathology will require further investigation.

Adult↗
PubMed1994

Alteration of the circadian rhythm of intact parathyroid hormone following a 96-hour fast.

OBJECTIVE: PTH(1-84) secretion in normal male subjects follows a circadian rhythm. The control of this rhythm is multifactorial with both neuroendocrine and chemical influences. The aim of this study was to assess the effect of a 96-hour fast on the circadian rhythm of PTH(1-84), serum calcium, phosphate and nephrogenous cAMP (NcAMP), an index of PTH(1-84) bioactivity. DESIGN: Blood samples for estimation of all analytes were obtained over a 24-hour period at 30-minute intervals. Urine samples were obtained 4 hourly during the daytime and overnight. Each subject was studied on two occasions after being randomized to either (a) normal hospital diet or (b) a 96-hour fast with water freely available. SUBJECTS: Six healthy adult males aged between 28 and 40 years, mean 32 years. MEASUREMENTS: PTH(1-84) was measured by an in-house immunoradiometric assay. Serum calcium, phosphate, albumin, creatinine and urinary creatinine were measured by standard automated techniques. Calcium was adjusted for albumin. Plasma cAMP was estimated by a commercial method and urine cAMP by in-house radioimmunoassay and NcAMP obtained by calculation. Rhythm parameters were analysed by cosinor techniques. RESULTS: There were alterations in the circadian rhythms of serum phosphate, PTH(1-84) and NcAMP following a 96-hour fast. Fasting abolished the nocturnal rise in phosphate, PTH(1-84) and NcAMP but had little effect on the pattern of adjusted calcium over a 24-hour period. The mean concentrations of serum phosphate, adjusted calcium and NcAMP decreased significantly following the fast and mean PTH(1-84) increased during day time. CONCLUSIONS: Fasting for 96 hours significantly alters the circadian rhythm of PTH(1-84) secretion by lowering the mean calcium concentration and attenuating the circadian rhythm of serum phosphate.

Adult↗
PubMed1991

"Mini-perforation" of the colon--not all postpolypectomy perforations require laparotomy.

In a 10-year experience with 4,784 consecutive colonoscopic polypectomies, the need for operative intervention in just two of seven perforations indicates that patients with specially defined, limited perforations can usually be treated nonoperatively. This specific complication, which has been termed "mini-perforation," is generally detected within 6-24 hours of polypectomy, and is characterized by local pain and tenderness, without signs of diffuse or spreading peritoneal irritation. Free intra-abdominal or retroperitoneal air on x-ray documents the actual perforation. Complete resolution of symptoms within 24-48 hours confirms the diagnosis of "mini-perforation." Success depends on good bowel preparation for colonoscopy, and early recognition of perforation, with institution of bowel rest and intravenous antibiotics. The "mini-perforation" spontaneously closes, probably by omental adherence. Frequent serial clinical examinations are mandatory so that frank perforation with advancing peritonitis will be promptly recognized and treated surgically. An understanding of the three levels of cautery injury to the colon wall--"serosal burn," "mini-perforation," and "frank perforation" are essential in managing the complications of colonoscopic polypectomy.

Anti-Bacterial Agents↗
PubMed1989

Direct and indirect measurement of the hepatic extraction ratio of indocyanine green in the rat.

1. In order to estimate liver blood flow in the rat, the extraction ratio of Indocyanine Green was determined using a two-compartment model fitted to the plasma concentration time data after a single intravenous bolus dose and compared with values obtained directly by transhepatic sampling, both in the intact rat and in an isolated perfused rat liver preparation. 2. There was no agreement between estimates of the extraction ratio obtained by using the kinetic model and the directly measured values. 3. Elimination curves for Indocyanine Green were simulated to yield varied clearance values. Despite a 250% variation in clearance, extraction ratios derived using the two-compartment model were all greater than 0.9 and varied by less than 6%. 4. Estimates of liver blood flow obtained by deriving a value of the extraction ratio of Indocyanine Green using the two-compartment model are inaccurate.

Animals↗
PubMed1988

Polypectomy or colectomy? Management of 106 consecutively encountered colorectal polyps.

Although malignant sessile colorectal polyps usually require colectomy for proper treatment, the majority of malignant pedunculated polyps can be removed colonoscopically. A polyp is considered malignant if the proliferating cells have penetrated the muscularis mucosa. Total excisional biopsy is necessary to properly assess an adenoma microscopically. Forceps biopsy is inadequate. Virtually all malignant pedunculated polyps can be removed colonoscopically, provided one can reach the lesion, and provided one is experienced with snare electro-surgical techniques. Certain sessile polyps can also be removed colonoscopically, if the lesion is soft and nonulcerated, and if one is familiar with piecemeal polypectomy technique developed by Shinya. If the adenoma is malignant, special attention microscopically must be given to the margin of transection, to the specimen's lymphatics, and to the degree of differentiation of the malignancy. If the margin transection and lymphatics are free of tumor cells, if the malignancy is well differentiated, and if follow-up endoscopic exam reveals no residual or recurrence at the polypectomy site (i.e., Morson criteria), the malignant polyp can be considered cured by colonscopic polypectomy alone. The author's experience with 106 consecutively encountered malignant colorectal polyps over a 10 year period is reviewed. Sixty two lesions were removed by colonscopic polypectomy alone. All patients in this group have done well, except for one patient who had tumor involvement at the margin of polyp transection, who was considered inoperable because of severe medical problems, and who died from hepatic metatases 5 months later. Forty four patients underwent colectomy; 26 of these colectomies were preceded by colonoscopic polypectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Malignant colon polyps--cure by colonoscopy or colectomy?

Although malignant sessile colon polyps usually require colectomy for proper treatment, the vast majority of malignant pedunculated polyps can be removed colonoscopically for cure. The author's experience with 83 consecutively encountered malignant polypoid lesions is reviewed and is the basis for the discussion herein. All 49 malignant pedunculated polyps were removed colonoscopically. Eight of these patients also underwent colectomy because of questionable or definite presence of cancer cells within the stalk portion of the polyp; no residual cancer was identified at the polypectomy site, and all lymph nodes were negative in these patients. Of 34 patients with malignant sessile polypoid lesions, 13 underwent colectomy because of obvious malignancy at colonoscopy. Twenty-one sessile lesions were removed colonoscopically; with malignancy documented, nine of the 21 patients underwent colectomy. Positive findings (either cancer at the polypectomy site or in lymph nodes) at surgery were identified in two of these nine patients. Colonoscopic polypectomy can be considered curative for malignant pedunculated polyps provided the stalk portion of the lesion is totally uninvolved with the malignant process, provided there is no lymphatic or vascular invasion, the malignancy is well differentiated, and follow-up endoscopic examination of the polypectomy site reveals no residual or recurrence. These four criteria must be satisfied in order to consider a malignant pedunculated polyp curatively removed by colonoscopic polypectomy alone. The risk of colectomy in patients satisfying these four criteria is believed to be greater than the risk of metastatic disease and death from this lesion. Colectomy is recommended for all patients with malignant sessile polypoid lesions, provided their general medical condition provides an acceptable operative risk. Although colonoscopic polypectomy is not recommended for obviously malignant sessile polyps, there are instances where sessile lesions are removed colonoscopically and found microscopically to contain focal or minute areas of invasive cancer. In certain of these patients, the risk of colectomy may exceed the risk of recurrence or metastasis, if the polypoid lesion has been totally removed colonoscopically and completeness of the polypectomy has been documented by follow-up colonoscopy. Each patient's clinical history, general condition, and histopathology must be reviewed individually by a clinician experienced in this field in order to reach a wise and proper decision regarding the potential need for colectomy, and limit colectomy to those patients in whom it is absolutely necessary.

Adenoma↗
PubMed1982

Technique of colonoscopic polypectomy.

Most colonic polyps can be removed colonoscopically from all reaches of the colon, provided that one is experienced with endoscopic morphology and snare electrosurgical techniques. Virtually all pedunculated polyps and the majority of benign sessile polyps can be excised colonoscopically, certain of the larger benign sessile polyps and all malignant sessile lesions still require partial colectomy, if the patient's general condition will permit. Preparation for colonoscopic polypectomy includes thorough mental as well as physical preparation of the patient and the availability of properly functioning endoscopic and snare-cautery equipment. An experienced colonoscopist is one who is not only prepared for the diagnostic possibilities but experienced enough to manage certain of the larger polyps so that laparotomy is limited to those few lesions that are not amenable to safe and total colonoscopic polypectomy.

Colonic Neoplasms↗
PubMed1979

Massive lower gastrointestinal bleeding from intestinal varices.

Lower gastrointestinal bleeding from intestinal varices cannot readily be detected at operation; hence, preoperative identification is important. Our experience with six patients having sudden, massive bleeding per rectum from intestinal varices suggests a group of common findings. These patients had cirrhosis, no blood in the stomach or duodenum, characteristic mucosal imprints on barium enema, or direct visualization of varices on sigmoidscopy or colonoscopy. Only two had demonstrable esophageal varices. The diagnosis was confirmed and the site of the varices localized on the venous phase of selective mesenteric angiography in five patients. Varices were located in the duodenojejunum in two, in the cecum and ascending colon in two, and in the rectum and sigmoid colon in two patients. Three patients were treated nonoperatively with transfusion and intraarterial infusion of vasopressin into the superior mesenteric artery; one died. One patient with cecal varices had a right hemicolectomy that controlled the bleeding, but progressive hepatic failure resulted in postoperative death. The remaining two patients had successful decompression of left colonic varices by portasystemic shunt.

Aged↗
PubMed1977

Colonoscopic excision of large sessile polyps.

Experience with 80 consecutively-encountered large sessile colon polypoid lesions is reviewed in order to document the salient principles involved with safe and total endoscopic excision of certain of these lesions. The endoscopic physical characteristics of the polypoid lesion is the single most important factor in determining the method of removal of sessile polypoid lesions. Considerable experience with diagnostic colonoscopy and endoscopic removal of pedunculated and small sessile lesions is most important before considering the technic of piece-meal polypectomy for large sessile benign lesions.

Adenoma↗
PubMed1976

Which colonic polyps should be excised endoscopically?

A review of 464 consecutive polypoid lesions of the colon reveals that virtually all pedunculated polyps and over 80% of 218 sessile polyps were removed colonoscopically. Although size or location of the lesions occasionally precludes colonoscopic excision, the endoscopic appearance of a sessile polyp is the most important factor in deciding upon the method of excision. In gneeral, smooth, soft, nonulcerated sessile lesions of all sizes were excised endoscopically, while approximately half of the larger (2-6 cm) firm, irregular-surfaced, benign sessile lesions, and all ulcerated or malignant sessile lesions required laparotomy for proper management. All polypoid lesions should be viewed endoscopically before deciding the method of excision, regardless of their size, location, or general appearnce by barium enema. Experience with endoscopic morphology and snare electrocautery technics was most important, since more than 85% of all polypoid lesions in this consecutive series were removed endoscopically.

Adenocarcinoma↗
PubMed1976

Fiberoptic colonoscopy: diagnostic value in 250 consecutive patients.

Endoscopic findings and accomplishments in 250 consecutive patients are presented. Of these patients 72% were found to have polyps, cancer, inflammatory bowel disease or other specific positive findings. In almost half of these patients, no definitive diagnosis had been made before the procedure. In half of the patients, new information was obtained which was not known before the procedure. Indications for colonoscopy are presented to demonstrate the situations in which the procedure was valuable not only to remove polyps, but also to explain nonspecific radiologic abnormalities, unexplained rectal bleeding, or diarrhea, and to detect unknown cancers and polyps.

Adolescent↗
PubMed1976

Colonscopic excision of sessile polyps.

Most benign sessile colon polyps can be removed colonoscopically from all reaches of the colon, thus avoiding laparotomy previously required for most of these lesions. Two hundred and fifty colonoscopy procedures were reviewed, revealing 87 sessile colon polyps ranging from 0.5-6.0 cm. in size. Sixty-eight of 87 lesions were excised from 51 patients with just three lesions found to be malignant (invasive adenocarcinoma). Sixteen lesions were felt to be unsuitable for safe colonscopic excision and were, therefore, removed by laparotomy (in 12 patients) and six lesions found to be malignant. Three sessile lesions in this consecutive series were not yet removed at the time of this writing. Thorough bowel preparation and evaluation for other possible lesions are important components of this procedure, which yielded other polyps or cancers in 24 of 66 patients. While most sessile lesions less than 2 cm. in size can be excised endoscopically, certain larger benign sessile lesions can also be removed using piece-meal snare excision technics and radiowave electrocautery (principle of less heat penetration and tissue destruction). Seventy-nine per cent of all sessile colon polyps were excised colonoscopically in this series making abdominal surgery now unnecessary for most colon polyps. Laparotomy is necessary for certain larger benign lesions and all sessile lesions containing invasive cancer.

Colon↗
PubMed1975

Indications for fiberoptic colonscopy.

In certain clinical situations, fiberoptic colonoscopy has proved most useful and effective as a diagnostic and therapeutic tool. Colonscopy is indicated to remove polyps when feasible and to rule out the presence of toher polyps or tumors undetected by barium enema. Patients with cancer of the colon should have preoperative colonoscopy to rule out the presence of undetected polyps or metachronous cancer. Follow-up examinations are important to insure against residual cancer or recurrence after colonscopic removal of sessile, premalianant, or malignant polypoid lesions, and to evaluate certain patients who have increased risk of polyp or tumor formation. Colonscopy usually can explain persistent, localized abnormalities detected by barium enema (ie, "filling defects") and provide a definitive diagnosis in cases of unexplained rectal bleeding or diarrhea despite negative sigmoidoscopic and barium studies. In experienced hands, this technic is safe, confortable, and effective in avoiding laparotomy to remove clinically significant polyps and in providing definitive diagnosis in many clinical situations.

Barium Sulfate↗