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Biomedical subjects

R Siewert

Publications and source records attributed to R Siewert.

At least 19 recordsLinked to original sources
PubMed1992

[Can gastroesophageal reflux be prevented by inducing a scar tissue ring around the cardia?].

Severe gastroesophageal reflux was accomplished in 18 dogs by circular cardiomyectomy. After this intervention a Vicryl scarf was placed around the cardia in 12 dogs. The Vicryl scarf was absorbed within 6 months and in its place remained a scarred tissue. In the follow up gastroesophageal reflux could not be detected by manometry, pH-metry, radiology and endoscopy. In the control group all 6 dogs died within 3 weeks due to complications of gastroesophageal reflux. On the basis of these data the Vicryl scarf implantation is an effective, simple, new antireflux operation which can be initiated into the human surgical practice.

Absorption↗
PubMed1989

[The transformation of gamma-tocopherol to alpha-tocopherol in the animal organism; a generational study in rats].

The biosynthesis of alpha-tocopherol, the most effective vitamer among the vitamin E-group, is found only in higher plants and microorganisms. Due to the lack of the shikimate pathway, animals are not able to synthesize alpha-tocopherol. Also not found is a whole enteral synthesis; only the conversion of dimethyletocol to trimethyletocol seems to be possible. Using four generations of rats, we sought to determine: Is a transformation of gamma-tocopherol to alpha-tocopherol in the animal body possible? Are there any differences in the transformation rates in organs, tissues, or in the entire body along the generations? Does gut flora play any role in the conversion of gamma-tocopherol? Is it possible to increase the efficiency of the transformation by supplying additional CH3-groups? Wistar rats were fed a semisynthetic basal diet, supplemented with 78.8 mg DL-gamma-tocopherol/kg in the first three generations (F1-F3). In the fourth generation (F4), some of the animals were fed a vitamin E-free diet and gamma-tocopherol (approx. 1.5 mg on alternate days) was injected s.c. Two other groups of animals received the basal diet containing additional methionine (0.25%) or choline (0.45%), as well as gamma-tocopherol (as in F1-F3). alpha- and gamma-tocopherol were analyzed by HPTLC in the whole body and in serum, liver, heart, lung, gut, gonads, and feces. The ratio of alpha-/gamma-tocopherol (micrograms/micrograms) as transformation rate and vitamin E-biopotency (microgram alpha-tocopherol equivalents/g) were calculated. Growth and fertility were normal until the fourth generation; no abnormal developments could be recognized. alpha-tocopherol was found in the whole-body as well as in all tissues and organs. In the whole-body, vitamin E-biopotency decreased 25-70% in F2 and F3. On the other hand, the increase of the transformation rate of gamma- to alpha-tocopherol amounted to 23% (F2) and 168% (F3). Highest conversion rates were found in F2 and F3 for feces, followed by gonads and lungs; the lowest rates were found for serum and liver. Due to the s.c. injection of gamma-tocopherol, feces showed a four-times lower transformation rate in F4 than in F3. There was an increase in heart, gut, lung and serum for both transformation rate and vitamin E-biopotency. These parameters could be improved also by the additional supplements of methionine and choline. Both methyl-group-donators revealed nearly the same positive effect. The results show that the animal organism can adapt to gamma-tocopherol supply over generations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Surgical considerations for antireflux therapy.

Surgery has a major role to play in the treatment of reflux disease. Several factors should be considered prior to utilising the surgical approach. Severity of the reflux disease and response to conservative treatment are generally acceptable criteria for deciding whether a patient should undergo a surgical procedure. Once the decision is made to utilise a surgical approach, a specialised centre with an abundance of experienced, skilled surgeons and a specialised diagnostic laboratory should be selected. It is the responsibility of the referring physician and surgeon to diagnose accurately the presence of reflux disease. Endoscopy, pH-metry, and manometry are useful in precisely diagnosing the presence of reflux disease. Fundoplication is the favoured surgical procedure. The most common complications associated with this procedure are gas bloat and hypercontinence, which are acceptable tradeoffs for reflux disease. The patient must be educated about the surgical procedure and its consequences prior to the operation and informed of the alternatives. Accurate diagnosis, coupled with selection of an experienced surgeon and patient education can have a dramatic impact on reflux disease in the individual patient.

Esophagitis, Peptic↗
PubMed1988

Effect of somatostatin on skin lesions and concentrations of plasma amino acids in a patient with glucagonoma-syndrome.

A case of glucagonoma syndrome in a 58-year-old male patient who had the typical skin lesions associated with severe hypoaminoacidemia is described. The decrease in amino acids has been proposed to be causally related to the dermatosis. Furthermore, it has been shown previously that somatostatin rapidly improves skin lesions in glucagonoma patients. Therefore, plasma amino acid levels were determined before and during an infusion of somatostatin prior to surgical removal of the tumor in the tail of the pancreas. During somatostatin infusion in combination with total parenteral nutrition, 10 out of 22 amino acids were in the normal range. Thus it seems unlikely that normalization of amino acid levels is responsible for the rapid improvement in skin lesions in glucagonoma patients. On the other hand it cannot be excluded that partial normalization of amino acids contributed to the observed healing process. Nevertheless, somatostatin administered prior to surgery is a useful therapeutic regimen in these patients.

Adenoma, Islet Cell↗
PubMed1979

[Cardia function after proximal-gastric vagotomy (author's transl)].

In 36 patients with chronic duodenal ulcer disease LES-function before and after proximal-gastric vagotomy was examined manometrically and by determining pH-values in a prospective study. In addition, esophagus biopsies were taken 5 cm proximal of the cardia. 12 healthy volunteers served as controls. A direct effect of proximal-gastric vagotomy on LES-function could not be shown. On the contrary, in 38,9% of the patients examined, preoperatively proven esophagitis disappears nearly completely 12 months following proximal gastric vagotomy. This positive effect of vagotomy is to be interpreted as a beneficial effect on regurgitated intestinal juice, more so than an effect on cardia function itself.

Adult↗
PubMed1979

[Transmural varices ligation and fundoplication as an emergency operation in acute esophageal varices hemorrhage].

In patients with bleeding esophageal varices the main purpose of the treatment is to stop the bleeding at a justifiable risk. The so-called blocking procedures reach this purpose most consistently. We report the results on transmural variceal ligation plus fundoplication in 16 patients in whom the bleeding esophageal varices were not stopped by conservative means. 75% of these patients belonged to group B and C in Child's classification. Postoperative lethality was 18,7%, in all cases bleeding was stopped. These results favour trasmural varices ligation as an emergency procedure in bleeding esophageal varices.

Emergencies↗
PubMed1979

[Differential diagnosis of postoperative fistulas of the urinary tract (author's transl)].

A case is demonstrated in which an indwelling intravenous catheter was pushed by mistake via V. subclavia and the right heart into the V. cava inf. There the catheter perforated the wall of the V. cava. The continued infusion induced a cystic retroperitoneal tumor. The puncture of this tumor was followed by a fistula that was misinterpreted as a fistula of the urinary tract.

Catheterization↗
PubMed1979

[The effect of Ca++ on gastrin output and LESP before and after antrectomy (author's transl)].

Previous investigations show that calcium infusion stimulates gastrin output in healthy volunteers, whereas after antrectomy calcium does not cause any significant change of IRG levels. Both healthy volunteers and antrectomized patients (B II) show a continuous increase of LESP, reaching a maximum after 120 minutes. These results suggest a direct interaction of Ca++-ions and gastrointestinal smooth muscle cells.

Adult↗
PubMed1979

Phasic and tonic types of smooth muscle activity in lower oesophageal sphincter and stomach of the dog.

Mechanical activity of isolated circular muscle strips from the lower oesophageal sphincter (LES), fundus, corpus and antrum of canine stomach was recorded. Nifedipine (10(-6) mol/l) selectively suppressed the phasic components of spontaneous, acetylcholine (ACh)- and noradrenaline (NA)-induced activity of gastric strips. The nifedipine-resistant tonic components of gastric strips were suppressed by nitroprusside sodium (NP) (10(-5) mol/l). LES strips exhibited only weak spontaneous activity. Their ACh-induced activation was nearly completely suppressed by nifedipine. Only NA was able to elicit a strong nifedipine-resistant activation which was, in contrast to the activation of fundus strips, not suppressed by NP.

Acetylcholine↗
PubMed1979

[Endobrachyesophagus and adenocarcinoma of the esophagus].

The columnar epithelium lined esophagus is usually the result of a chronic reflux disease. In the literature one can find more and more references to a malignant transformation of this columnar epithelium. Our own observations of 14 patients with an adenocarcinoma in a columnar-lined esophagus support this suspicion. Because the adenocarcinoma of the esophagus has therapeutic consequences other than a squamous carcinoma of the esophagus, the surgery has to give attention to this malignant transformation of the columnar-lined esophagus.

Adenocarcinoma↗
PubMed1978

[Reflux esophagitis: surgical indications (author's transl)].

Reflux esophagitis is a benign disease. Therefore, therapeutic indications are of special significance. Surgery is undisputed in cases of failure of conservative therapy. For the first time reliable data are available on the effectiveness and on the barriers of conservative therapy, because of initial results from double blind studies. According to these results, healing of reflux esophagitis of grades I and II can be expected under conservative therapy. However, most of the patients in grades III to IV, resisted conservative therapy, so an operation is indicated.

Age Factors↗