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Biomedical subjects

A D Newcomer

Publications and source records attributed to A D Newcomer.

17 recordsLinked to original sources
PubMed1979

Absorption of nutrients in lactase deficiency.

The influence of malabsorption of lactose, as a result of primary lactase deficiency, on the absorption of the nutrients in milk was tested in four healthy controls and four subjects with lactase deficiency. An ileal perfusion technique was used to quantify arrival in the ileum of nutrients and a nonabsorbable marker (polyethylene glycol, PEG 4000) ingested as a test meal of milk. The meal was 250 ml of whole milk or milk in which the lactose had been hydrolyzed to glucose and galactose. In the fasting state, ileal flow of volume, protein, carbohydrate, and electrolytes was small and not different in controls and lactase-deficient subjects. Ileal flow increased in all subjects after the test meal of milk; more fluid and nutrient was recovered from the ileum in lactase-deficient subjects after whole milk than in control subjects or in lactase deficiency after hydrolyzed milk. Two deficient subjects showed marked malabsorption of lactose (35 and 50%); two did not. Protein, calcium, magnesium, and phosphorus were also recovered from the ileum in greater quantities in lactase deficients after whole milk. However, apart from decreased absorption of lactose, the nutritional consequences of malabsorption in association with primary lactase deficiency in adults are probably minimal.

Adult↗
PubMed1979

Gallium scan: clue to diagnosis of starch peritonitis.

A patient with starch peritonitis was given a gallium scan which showed diffuse uptake in the abdomen and intense uptake in a noninfected incision six weeks after surgery. The accumulation of gallium in a noninfected surgical incision later than one week after surgery, accompanied by diffuse abdominal uptake, may indicate the presence of starch peritonitis.

Abdomen↗
PubMed1979

Triolein breath test: a sensitive and specific test for fat malabsorption.

In order to develop a simple and accurate screening test for steatorrhea, the authors compared quantitative stool fat excretion with breath excretion of 14CO2 after the ingestion of 14C-labeled trioctanoin, tripalmitin, or triolein. The study group included 24 nonobese subjects without steatorrhea but with diarrhea secondary to irritable bowel syndrome and 40 subjects with steatorrhea. The triolein breath test provided the most reliable discrimination, with 100% sensitivity and 96% specificity. The trioctanoin and tripalmitin breath tests were sensitive, but lacked specificity (69% and 58% false-positive results, respectively). Three of the 12 obese patients with irritable bowel syndrome had false-positive triolein breath results. In detecting steatorrhea, the triolein breath test was moderately superior to the measurement of serum carotene and to qualitative stool fat. Thus, the triolein breath test appears to be a sensitive, specific, noninvasive, and relatively simple screening test for the detection of steatorrhea.

Adult↗
PubMed1978

Lactase deficiency: prevalence in osteoporosis.

We determined the prevalence of lactase deficiency by analysis of respiratory hydrogen (H2) in 30 women with idiopathic postmenopausal osteoporosis and in 31 female control subjects without evidence of metabolic bone disease. Eight subjects with osteoporosis had breath H2 excretion greater than 0.20 ml/minute at 2 h after receiving 50 g of lactose and were considered lactase deficient; only one control subject was lactase deficient (P less than 0.05). Symptoms developed in seven of the nine lactase-deficient persons after receiving 50 g of lactose; in contrast, only three of the 52 lactase-normal subjects had symptoms. Although none of the lactase-deficient subjects was aware of milk intolerance, their intake of both lactose and calcium was significantly lower than that in the lactase-normal group. Lactase deficiency appears to be one of several factors that predispose to the development of osteoporosis, probably through diminished calcium intake and possibly through an effect on calcium absorption.

Aged↗
PubMed1978

Tolerance to lactose among lactase-deficient American Indians.

To determine the amount of lactose that could be tolerated in a meal, 59 lactase-deficient American Indians, ranging in age from 5 to 62, were given graded doses of lactose. The diagnosis of lactase deficiency had beeen documented previously by showing increased breath hydrogen after an oral lactose load (2 g per kg, maximum 50 g). With this load, 88% of the subjects had symptoms. On 6 consecutive mornings, each subject was given a breakfast that contained graded doses of lactose ranging from 0 to 18 g. The order of the breakfasts was randomized and the contents were double-blinded. Symptoms, which were assessed by a "blinded" observer, were present after 9% of the breakfasts at all dosage levels, including the lactose-free breakfast. Thus, under the conditions of this study, a modest amount of lactose, equivalent to that present in 1 to 1 1/2 glasses of milk, when taken with a meal, is well tolerated by the lactase-deficient American Indian.

Adolescent↗
PubMed1978

Clinical value of the bile acid breath test. Evaluation of the Mayo Clinic experience.

The Mayo Clinic experience with more than 200 bile acid breath tests was analyzed retrospectively to assess its clinical value. In patients with suspected bacterial overgrowth, the result of the bile acid breath test was compared with that of culture of aspirates of small bowel, and the test was found to have a sensitivity of 0.70 and a specificity of 0.90 (1.0 highest possible value). Although in one-third of the patients with a positive small-bowel culture the bile acid breath test failed to demonstrate the presence of bacterial overgrowth, analysis of the data according to the Bayes theorem showed that, compared with a routine evaluation without a small-bowel culture, the availability of breath test results will double the probability with which the clinician can be certain about the presence or absence of bacterial overgrowth. The test result appeared to influence the diagnosis in 83% and the management in 74% of the 163 patients in whom it was performed because of suspected bacterial overgrowth. In patients with suspected malabsorption of bile acids, on the other hand, the test that was performed without determination of fecal bile acid excretion appeared to be rather insensitive, and only rarely was information gained that was not already known from a routine workup of the patient.

Bacterial Infections↗
PubMed1977

Abdominal pain caused by diabetic radiculopathy.

In diabetes mellitus, pain and weakness in a lower extremity can result from lumbosacral radiculopathy. However, abdominal pain caused by a similar type of thoracic nerve root disease is not generally recognized. Four diabetic patients with abdominal pain were studied. In none of the patients was the actual cause--radiculopathy--suspected until after extensive negative diagnostic investigation, which frequently included invasive procedures. Their clinical features were suggestive of malignant disease. Electromyographic examination revealed the correct diagnosis, and all four of the patients had a spontaneous and complete recovery.

Abdomen↗
PubMed1977

Lactase deficiency: a common genetic trait of the American Indian.

Intestinal lactase activity was assessed indirectly in 156 American Indians by measuring breath hydrogen after an oral lactose load. Lactase deficiency was present in 66% of subjects and correlated highly with the percentage of Indian blood. Lactase deficiency was present by the age of 5 years and was unrelated to sex. Most lactase-deficient subjects (81%), but only a minority (23%) of lactase-sufficient subjects, developed symptoms after the oral lactose load, and among lactase-deficient subjects, symptoms occurred more frequently in adults than in children (P = 0.05). Indeed, by history, 53% of lactase-deficient adults, but only 10% of lactase-deficient children under 18 years of age, were aware of milk intolerance. Despite these differences, milk consumption was only slightly less (19 g) in the lactase-deficient subjects than in those with normal lactase activity (25 g) (P less than 0.05). The results indicate that lactase deficiency is a common autosomal genetic trait in the American Indian that becomes manifest in early childhood. Tolerance to dietary lactose appears to decline in the American Indian as he reaches adulthood, but in this population the decline in tolerance had only minor influence on lactose intake.

Adolescent↗
PubMed1977

Family studies of lactase deficiency in the American Indian.

To determine the pattern of inheritance of lactase deficiency, we studied 104 American Indian and 2 white subjects in 19 families. Subjects were considered deficient in lactase if breath-hydrogen excretion exceeded 0.20 ml per min above fasting at 2 hr after a lactose load of 2 g per kg of body weight (maximum 50 g). Seventy-one per cent of the males and 75% of the females were lactase deficient. In three families in which both parents were lactase normal, 40% of the children were lactase deficient; and in the three families with one parent lactase normal and the other lactase deficient, 65% of the children were deficient in lactase; and finally, in the seven families with both parents lactase deficient, 93% of the children were lactase deficient. This distribution of lactase deficiency in the families suggests that this trait shows an autosomal-recessive pattern of inheritance.

Adolescent↗
PubMed1975

Prospective comparison of indirect methods for detecting lactase deficiency.

To compare sensitivity, specificity and convenience, four indirect methods of detecting lactase deficiency were tested prospectively in 25 subjects with biopsy-proved lactase deficiency and in 25 with normal lactase activity. After ingestion of 50 g of lactose, containing 1-14Clactose, breath hydrogen was abnormally elevated in all 25 lactase-deficient subjects (greater than 0.30 ml per minute at two hours); breath 14CO2 was below the normal range in 23, and in 19 the plasma glucose increased by less than 20 mg per deciliter. When lactose and ethanol were given together, the rise in plasma galactose remained less than 5 mg per deciliter in 24 of the lactase-deficient subjects. The specificity of the four tests was excellent, with only one false-positive plasma glucose test. Measurement of breath hydrogen is sensitive and specific, and does not require ethanol or isotopes. It is noninvasive, and is not influenced by gastric emptying or metabolic factors. We believe it to be the most suitable test for population screening for lactase deficiency.

Adult↗
PubMed1975

Drug-induced malabsorption.

Pharmacologic agents of diverse types may alter gastrointestinal absorption of nutrients and other substances. Mechanisms underlying drug-induced absorptive defects that have been documented include: (1) a direct toxic effect causing morphologic changes in the mucosa of the small intestine; (2) inhibition of mucosal enzymes with or without morphologic evidence of mucosal damage; (3) binding and precipitation of micellar components, such as bile acids and fatty acids; and (4) alteration of the physicochemical state of another drug or dietary ion. The malabsorptive effect generally is dose-related, rather than an idiosyncratic reaction, and usually involves multiple nutrients. Certain clinical states, such as in the malnourished alcoholic may predipose the gastrointestinal tract to a drug-induced absorptive defect. For this review we discuss in detail nine commonly used drugs or types of drugs that cause malabsorption of dietary nutrients or other medications.

Alcoholism↗
PubMed1975

Intraluminal duodenal diverticulum. Report of two cases and review of the literature.

Diverticula rarely occur within the lumen of the duodenum. They arise near the papilla of Vater and extend distally. The diverticulum is lined on both sides with duodenal mucosa, and its eccentric opening is usually proximal in the sac. The diverticulum results from incomplete recanalization of the intestinal lumen after the proliferative epithelial stage in the 7-week embryo and represents either a remnant of one of two channels formed during recanalization or a distal ballooning of a congenital duodenal diaphragm. Although the patient with a diverticulum may be asymptomatic, most patients present with abdominal pain and obstructive symptoms; pancreatitis and gastrointestinal bleeding may be associated with the diverticulum. Barium study shows a characteristic radiolucent halo that represents the wall of the diverticulum. Surgery should be approached with caution because injury to the papilla is a hazard, and in children, coexisting congenital anomalies may be present.

Adult↗