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Biomedical subjects

J Kewenter

Publications and source records attributed to J Kewenter.

At least 19 recordsLinked to original sources
PubMed1992

Sodium and potassium excretion before and after conversion from conventional to reservoir ileostomy.

Sodium and potassium in the ileostomy output and urine were determined in 28 patients with ulcerative colitis on a free diet and in eight patients on a defined constant diet, before and after conversion from a conventional ileostomy (CI) to a continent reservoir ileostomy (RI). Feces and urine were collected both in the hospital and at home. Patients with CI on free diet had a median intestinal loss of 62 mmol sodium and those with RI 74 mmol/24 h collected in the hospital (p < 0.05). The figures for at home was 79 and 81 mmol/24 respectively, and were larger than in the hospital (p < 0.01). Sodium loss in the urine (U-Na) and the intake of sodium did not change significantly after conversion. Patients with a low U-Na before conversion also had a low U-Na after, in a few almost nil, implying a need for increased intake of sodium. Patients with a CI and low urinary output of sodium should be carefully studied with respect to their sodium balance before accepting them for conversion to RI. The ileostomy output of potassium increased after conversion (4.3 vs. 6.8 mmol/24 h; p < 0.01) in the hospital (5.3 vs 7.1 mmol/24 h; p < 0.01) at home. Patients on a defined constant diet before and after conversion did not show any significant differences in absorption of sodium, potassium, magnesium or calcium after conversion, but did show a reduced dry weight of the ileostomy output, indicating an increased degradation of intestinal contents in RI patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The anatomic range of examination by fibreoptic rectosigmoidoscopy (60 centimetres).

The purpose of the study was to investigate the anatomic location of the flexible rectosigmoidoscope (60 cm) when introduced as far as technically possible. One hundred and forty-nine consecutive patients referred for double-contrast enema (DCE) were examined with rectosigmoidoscopy before the radiologic examination, and CO2 was used for insufflation. A plain abdominal film was taken to locate the tip of the instrument when 60 cm or as much as possible of the instrument had been introduced. The sigmoid loop was passed and the tip of the scope located in the ascending colon or at the left flexure in 99 (66%) of the patients, and in a further 27 (18%) the upper part of the sigmoid colon was reached. The sigmoid colon had been passed in 71%, 80%, and 44% when 60, 50, and 40 cm of the instrument was introduced, respectively. DCE could be performed at the same session as the rectosigmoidoscopy, as CO2 was quickly absorbed. In the vast majority of patients the sigmoid colon can be inspected with a rectosigmoidoscope.

Adult↗
PubMed1990

Double contrast barium enema and flexible rectosigmoidoscopy: a reliable diagnostic combination for detection of colorectal neoplasm.

The efficiency of double contrast barium enema and flexible rectosigmoidoscopy (to 60 cm) in the assessment of patients with a positive Hemoccult II test in a randomized screening study for colorectal neoplasms was evaluated. A positive test was present in 625 patients, of whom 530 had a complete enema and rectosigmoidoscopic assessment. A carcinoma was diagnosed in 26 and an adenoma greater than or equal to 1 cm in diameter in 71. As a control, 323 patients with a negative assessment repeated the Hemoccult II test and of these 67 had a positive second test, of whom 55 underwent colonoscopy. One carcinoma (Dukes' A) and two adenomas greater than or equal to 1 cm in diameter were diagnosed. The efficiency of the assessment was also checked by rescreening the whole group 1-2 years after the first study and by continuing follow-up. It was found that two more carcinomas and one adenoma greater than or equal to 1 cm in diameter had been overlooked at the primary assessment. The sensitivity for neoplasms greater than or equal to 1 cm in diameter at the primary assessment was 72 per cent for double contrast barium enema and 86 per cent for rectosigmoidoscopy. The sensitivity for the combined methods was 94 per cent and the specificity was 99 per cent. The combination of double contrast barium enema and rectosigmoidoscopy in the primary assessment of patients with a positive Hemoccult II test gives an acceptable result and immediate retesting of those with a negative assessment is not necessary.

Adenoma↗
PubMed1990

Value of retesting subjects with a positive Hemoccult in screening for colorectal cancer.

Within a prospective randomized screening study for early detection of colorectal cancer with rehydrated Hemoccult II test, the possibility of increasing the specificity of the test by retesting patients with an initially positive Hemoccult II test was investigated. Of those offered the test 3561 (62.6 per cent) returned it and it was positive in 210 cases (5.9 per cent). The repeat test was performed by 184 patients and was positive in 68 (1.9 per cent). All those with a positive initial test had rectosigmoidoscopy to 60 cm and a double contrast enema. A carcinoma was found in one in seven patients with a positive retest but in only one in 100 patients with a negative retest (P less than 0.001). The specificity of the test was, therefore, increased from 95 per cent to 98 per cent and the sensitivity was unchanged. Rescreening was offered at a later date and increased numbers were available: 7147 patients returned the test and 369 (5.2 per cent) were positive. The test was repeated in 360 patients and 118 (1.7 per cent) were positive. A colorectal neoplasm was found in one in three of those with a positive repeat test, compared with one in seven of those with a negative repeat test. In conclusion, screening for early detection of colorectal cancer with a rehydrated Hemoccult II test may be followed by investigation of only those patients with a positive retest. Such a procedure will reduce the work-load by 60 per cent without reducing sensitivity.

Barium Sulfate↗
PubMed1989

Value of a risk questionnaire in screening for colorectal neoplasm.

The value of a postal questionnaire and of Hemoccult II (Smith Klein Diagnostic Inc., Sunnyvale, California, USA) testing in screening for colorectal neoplasms was compared. In the questionnaire, the subjects were asked about previous treatment for colorectal neoplasm and rectal bleeding during the previous 6 months, specified as to type. All participants were asked to perform Hemoccult II blood testing over 3 days. Of 13,759 randomly selected subjects 9040 (66 per cent) performed the test and returned the questionnaire. Three hundred and fifty-four subjects with a positive Hemoccult II test and/or a proven previous colorectal neoplasm had a full assessment including double-contrast enema and rectosigmoidoscopy to 60 cm. Eighteen carcinomas and 61 adenomas were thus diagnosed. The population was followed for from 20 to 29 months, during which time rescreening was undertaken. An additional 34 subjects with carcinomas and 90 with adenomas were identified during this period. A significant correlation between the presence of a colorectal neoplasm and a previous history of colorectal neoplasm, a positive Hemoccult II and a previous history of bright red bleeding but not dark bleeding was found. The possibility of diagnosing a neoplasm was two, four and 19 times higher in a subject with a previous history of bleeding, a history of colorectal neoplasm, or a positive Hemoccult II respectively. Screening by faecal occult blood testing, therefore, at the moment seems to be the best and only practicable method.

Adenoma↗
PubMed1988

Screening and rescreening for colorectal cancer. A controlled trial of fecal occult blood testing in 27,700 subjects.

All inhabitants of the city of Göteborg who in 1982 were between 60 and 64 years of age (27,700) were randomly divided into a test and a control group. The 13,759 subjects in the test group were invited to perform Hemoccult II (Smith Kline Diagnostic, Sunnyvale, CA) fecal occult blood testing over 3 days and to repeat the testing after 16 to 22 months. At the first screening 9,040 (66%) completed the test, and 7,770 (58%) completed the test at the second screening. In the first screening the test group was divided into two subgroups in which the tests were rehydrated and unhydrated before development. All tests were rehydrated in the second screening; 1.9% and 5.8% of the tests were positive in the unhydrated and rehydrated subgroups, respectively. The number of diagnosed neoplasms in the first screening was significantly larger (P less than 0.01) in the rehydrated group compared to the unhydrated group, 50 and 24 neoplasms, respectively. Sixteen of 61 carcinomas in the test group were found in the interval between the two screenings, 19 of the carcinomas at the second screening, and ten among the nonresponders. Rehydration of the Hemoccult II test is a necessity. Significantly more carcinomas (61) were found in the test group compared to the control group (20). There was a trend toward favorable tumor staging in the test group compared to the control group.

Clinical Trials as Topic↗
PubMed1987

Perception errors with double-contrast enema after a positive guaiac test.

Between 3 and 6 of 12 colorectal neoplasms larger than 1 cm in diameter were overlooked by each of 4 radiologists in 117 individuals investigated with double-contrast enema (DCE) after a positive guaiac test. Even when the individual results of 2, 3, or 4 experienced radiologists were combined, 2 small carcinomas were overlooked due to perception errors. One of these carcinomas was diagnosed by rectosigmoidoscopy, which is an important and necessary complement to DCE. Although small carcinomas may be missed even with this combination, meticulous exploitation of the 2 methods is absolutely necessary to minimize the risk of missing a colorectal neoplasm. A drawback when 2 or more radiologists read the radiographs is the increased number of false-positive findings.

Adenoma↗
PubMed1986

Diagnostic accuracy of double-contrast enema and rectosigmoidoscopy in connection with faecal occult blood testing for the detection of rectosigmoid neoplasms.

Four hundred and fifty-eight consecutive subjects with a positive faecal guaiac test when screened for early detection of colorectal neoplasms were investigated with double-contrast enemas and rectosigmoidoscopy (60 cm). The results of these two methods were compared. The radiologists and endoscopists were unaware of the result of each others' examination at the time of their own investigation. Altogether ten subjects with carcinoma in the rectosigmoid area were found. The radiologists and endoscopists each overlooked four of these ten carcinomas and only four of the carcinomas were diagnosed with both methods. Fifty-six of one hundred and seven adenomas were 1 cm or larger in diameter and located in the rectum or the sigmoid colon. Thirteen of the fifty-six adenomas were missed by double contrast enema and ten by endoscopy and only thirty-three adenomas were diagnosed with both methods. Neoplasms in the rectum and the sigmoid colon are sometimes difficult to diagnose with both radiology and endoscopy. Rectosigmoidoscopy (60 cm) should therefore be used as a complement to double contrast enemas if this method is chosen for investigation of a patient with rectal bleeding.

Adenoma↗
PubMed1985

Diverticular disease and minor rectal bleeding.

The purpose of the study was to compare the history of rectal bleeding during the year before the study and the presence of faecal occult bleeding in patients with advanced diverticular disease of the large bowel and two sex- and age-matched reference groups, one consisting of patients with normal large-bowel barium enemas and the other of persons without any history of gastrointestinal disease. The number of persons with faecal occult bleeding or macroscopic anal bleeding during the year before the study was not increased in the group with diverticular disease as compared with the other two groups. The bleeding frequency and characteristics of the bleeding did not differ among the three groups. It is concluded that minor rectal bleeding is rather uncommon in persons with uncomplicated diverticular disease. Patients with a history of rectal bleeding in whom a barium study has only shown diverticular disease should be further investigated as though the diverticula were not present.

Aged↗
PubMed1979

The effects of splanchnic nerve stimulation on the plasma levels of serotonin and substance P in the portal vein of the cat.

The blood levels of serotonin (5-HT) and substance P (SP) in the portal vein were studied after splanchnic nerve stimulation in the cat. The portal levels of both substances were studied before, during and after splanchnic nerve stimulation. There was a twofold increase in 5-HT during stimulation whilst the SP concentration remained unchanged. These results suggest that the nervous control of the amine release into the portal stream and the mechanism that regulates the release of the polypeptide is not the same.

Animals↗
PubMed1979

The effect of transmural field stimulation on the serotonin content in rat duodenal enterochromaffin cells--in vitro.

The effect of transmural field stimulation (TFS)--in vitro--on the sertonin (5-HT) content in enterochromafffin cells (EC) in rat duodenum was studied with a cytofluorimetric method. TFS caused a significant 25% decrease of 5-HT in EC. The presence of tetrodotoxin or d,1-propranolol in the stimulation bath antagonized the effect of TFS. In biopsies from rats pretreated with 6-OH-dopamine TFS had no effect of the 5-HT content in EC. The results of the present study strongly suggest, that the TFS induced decrease in 5-HT content is due to a direct neural, probably beta-adrenoceptor mediated, influence on the EC.

Adrenergic Fibers↗
PubMed1979

The vagal control of the feline pyloric sphincter.

In acute experiments on cats in chloralose anesthesia the effects of efferent and afferent electrical stimulation of the cervical vagi on an applied constant flow of saline through the feline pylorus was studied. The motor activity of the stomach was recorded simultaneously with a volume recording technique. Efferent cervical vagal stimulation caused a decrease in the transpyloric flow and an increased gastric motor activity. In a few animals the decreased transsphincteric flow was preceded by a short period of increased flow. When the transpyloric flow was reduced by splanchnic nerve stimulation or a noradrenaline infusion, vagal nerve stimulation induced an increased flow through the pylorus indicating the presence of relaxatory fibres to the pylorus within the vagi. Electrical stimulation of the central end of the ipsilateral vagal nerve in the neck, with the contralateral vagal verve left intact, resulted in a decreased transpyloric flow and relaxation of the stomach. This response could be induced with or without intact splanchnic nerves, and disappeared when the intact contralateral vagus was cut. It is concluded that the vagi mediate both excitatory and inhibitory fibres to the pyloric sphincter in the cat. A vago-vagal excitatory reflex to the pylorus can be elicited by afferent vagal nerve stimulation together with a vago-vagal relaxatory response of the stomach.

Afferent Pathways↗