Biomedical subjects
Publications and source records attributed to A M Nielsen.
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Antral vascular ectasia or "the watermelon stomach" (WS) is an endoscopically, histologically and clinically distinct entity. The term WS reflects the endoscopic appearance of longitudinal antral erythematous folds containing visible vessels radiating from the pylorus. Histological examination demonstrates characteristic features including dilated mucosal capillaries, focal thrombosis and fibromuscular hypertrophy of the lamina propria. The clinical picture is characterized by severe chronic iron deficiency anaemia, and failure to recognize WS has frequently delayed adequate treatment for several years. Antrectomy is a definitive cure. Both endoscopic laser- and sclerotherapy seem to be promising alternative methods in the treatment of WS.
An unexpectedly large number of peritoneal mesotheliomas among women was reported to the Danish Cancer Registry during the years 1960 through 1985. In a case-control study, we tested whether this was due to diagnostic misclassification or to direct exposure of the peritoneal membranes to talc during abdominal surgery. Tissue specimens were available from 96 reported peritoneal mesotheliomas; 35 cases (37%) were regarded as verified mesotheliomas, and 33 (34%) as possible mesotheliomas. Information on any intraabdominal surgery was obtained from the hospital records of these 68 cases and for 206 controls with a cancer of the uterine corpus or pancreas. No association was seen between peritoneal mesotheliomas and abdominal surgery performed more than 25 years prior to cancer diagnosis (odds ratio, 0.83; 95% confidence interval, 0.35-1.94). CONCLUSION. Misclassification of other cancers was the reason for the observed excess of peritoneal mesotheliomas.
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Although until recently the reduction of gastric acid secretion was the primary aim in the treatment of peptic ulcer disease, it is now recognised that the presence of Helicobacter pylori and not only acid is required to produce duodenal ulcer. Accordingly, the part played by gastric acid has been relegated to the contributor to the effects of H pylori infection. Recent research into the pathogenesis and treatment of peptic ulcer disease suggests the locus of receptors for acid stimulants, such as acetylcholine, histamine and gastrin, to be the immune cell in the lamina propria of gastric mucosa, and not the parietal cell. Thus the effects of acid stimulants, as well as those of mediators of other gastro-intestinal functions, such as oesophageal and gastroduodenal bicarbonate secretion, may be directly transmitted to the effector cells via macrophages and plasma cells. Nitric oxide (NO) may be the agent mediating the interaction between immune and epithelial cells. If these findings are validated and confirmed in man, they may pave the way for new approaches to the treatment of acid-related disorders, resulting in therapeutic strategies that do not necessitate the eradication of H pylori.
Information from the Danish National Patient Register revealed that 817 patients had been hospitalized with verified whooping cough during the period 1980-1986. The letters of discharge or the case records were obtained for all patients under one year for the entire period and for all patients over one year for the period 1984-1986, a total of 627 persons. These were supplemented by information from forms with information about positive cultures for whooping cough in nasopharyngeal swabs and from individual notifications about children under one year. 65% of the hospitalized patients were under one year and only 2% over 15 years. The severity of the disease measured by the duration of hospitalization and the presence of serious complications and symptoms decreased with age. The average duration of hospitalization was 15 days for children under one year and seven days for children over one year. Five children died. One child developed epilepsy, nine of the remainder required assisted respiration and recovered apparently without permanent damage. Out of the 627 patients who were hospitalized, pneumonia developed in 12%, seizures in 2% under one year and 5% over one year, apnoea occurred in 10% under one year and 2% over one year and cyanosis occurred in 61% under one year and 30% over one year. None of the vaccinated children developed seizures, required assisted ventilation or died and only 2% had apnoea as compared with 7% in the unvaccinated children. Children under two months and children in whom vaccination was contraindicated were responsible for 56% of the hospitalizations among children under one year and for 79% of the most severe cases.(ABSTRACT TRUNCATED AT 250 WORDS)
On the basis of individual notifications, reports of cases verified by culture and letters of discharge or case reports of infants under one year with whooping cough during the period 1980-1986, the distribution of the disease is described together with vaccine efficacy and the presumed sources of infection for infants in this age group. The incidence of whooping cough in infants under one year is estimated to be approximately three cases per 1,000 per annum as compared with 150 per 1,000 at the beginning of this century and 60 per 1,000 in the nineteen fifties before routine vaccination was introduced in 1961. The first vaccination is calculated to provide a vaccine efficacy of 39%, after the second vaccination the vaccine efficacy rises to 86% and after the third vaccination the vaccine efficacy is about 98% during the remainder of the first year of life. Even although the times of vaccination were advanced in 1970, this has not reduced the frequency of whooping cough in infants as the vaccination programme has simultaneously been weakened because children are now vaccinated only three times with a weaker vaccine and the immunity is of briefer duration. The commonest sources of infection for infants are siblings. A lower infective risk is desirable and this could be obtained by vaccinating infants an extra time. Alterations in the system of notification in 1980 have resulted in increased under-notification of whooping cough in children under one year while, simultaneously, the notified cases have been described better.
The effect of prolonged hypercapnia on carotid chemoreceptor discharge frequency has not been elucidated. In addition, the effect of acute hypercapnia on chemoreceptor discharge has not been determined in the goat, a species commonly used for ventilatory control studies. Therefore, we determined the effects of acute and prolonged normoxic-hypercapnia on single fiber output of the carotid body of chloralose anesthetized goats. The animals were paralyzed and artificially ventilated. The average acute response curve for 12 single fibers was linear over the range of 30-80 Torr PaCO2 with a mean slope of 0.115 +/- 0.057 (SD) imp.sec-1.Torr-1 PaCO2. Elevated discharge frequency was maintained during prolonged (up to 240 min, n = 11) steady-state hypercapnia (X PaCO2 = 85 Torr). No systematic time-dependent changes in afferent discharge frequency occurred during the period. The findings obtained during sustained hypercapnia are in contrast to the time-dependent increase in carotid body activity seen previously in our laboratory with prolonged normocapnic-hypoxia of up to 240 min duration.
The present study revealed an incidence of maltreatment of 26.8 in 100,000 children under 15 years of age, higher than previously assumed. The sample comprises 41 children suspected of having been maltreated. A systematic examination included radiography and isotope scintigraphy of the skeletal system. In 9 cases the diagnosis was not confirmed, in 23 confirmed, and in 9 children it seemed likely. The most common form of maltreatment was physical violence with bruises. A total of 6 fractures were demonstrated. Three children had been exposed to sexual abuse. Intracranial haematoma, of long standing, was found in one child. Thirteen of the children (40%) were of short statute, their height and weight below the 25th percentile. Among 27 children examined by X-rays 16 (59%) had delayed skeletal maturation. Disturbances of growth, as well as behavioural abnormalities, were particularly striking in this group of patients. The findings suggest that even the slightest suspicion of maltreatment should lead to a general medical evaluation without delay.
The role of carotid body chemoreceptors in ventilatory acclimatization to hypoxia, i.e., the progressive, time-dependent increase in ventilation during the first several hours or days of hypoxic exposure, is not well understood. The purpose of this investigation was to characterize the effects of acute and prolonged (up to 4 h) hypoxia on carotid body chemoreceptor discharge frequency in anesthetized goats. The goat was chosen for study because of its well-documented and rapid acclimatization to hypoxia. The response of the goat carotid body to acute progressive isocapnic hypoxia was similar to other species, i.e., a hyperbolic increase in discharge as arterial PO2 (PaO2) decreased. The response of 35 single chemoreceptor fibers to an isocapnic [arterial PCO2 (PaCO2) 38-40 Torr)] decrease in PaO2 of from 100 +/- 1.7 to 40.7 +/- 0.5 (SE) Torr was an increase in mean discharge frequency from 1.7 +/- 0.2 to 5.8 +/- 0.4 impulses. During sustained isocapnic steady-state hypoxia (PaO2 39.8 +/- 0.5 Torr, PaCO2, 38.4 +/- 0.4 Torr) chemoreceptor afferent discharge frequency remained constant for the first hour of hypoxic exposure. Thereafter, single-fiber chemoreceptor afferents exhibited a progressive, time-related increase in discharge (1.3 +/- 0.2 impulses.s-1.h-1, P less than 0.01) during sustained hypoxia of up to 4-h duration. These data suggest that increased carotid chemoreceptor activity contributes to ventilatory acclimatization to hypoxia.
Dopamine (DA) is generally accepted to be an inhibitory neurotransmitter in the carotid body (CB). It is released and depleted from the CB by acute hypoxia. From this background we made the hypothesis that hypoxic depletion of CB DA could be responsible for a time-dependent increase in CB afferent output and the early phase of ventilatory acclimatization to hypoxia (VAH) in goats. We reasoned, then, that blockade of DA receptors in the CB would accelerate the time course of VAH in the goat, i.e. produce a greater acute response to hypoxia (first 15 min) followed by a reduced rate of change of the subsequent time-dependent hyperventilation. We tested this hypothesis by exposing 7 adult female goats to up to 28 h of hypobaric hypoxia (PB = 380 Torr) on 3 different occasions separated by at least 2 months. The first was as control. During the second and third exposures different doses of the DA antagonist, domperidone, were administered prior to and during the hypoxic exposure (0.5 mg/kg followed by 0.25 mg/kg every 3 h and in the second study 1.0 mg/kg followed by 0.5 mg/kg every 2 h). The time course of acclimatization was assessed by measurement of arterial blood gases and pH in the awake goats. The data obtained in the first 4-5 h of hypoxia in domperidone treated animals appeared to support the hypothesis. Domperidone treated animals had a significantly greater acute ventilatory response to hypoxia followed by a lower rate of progressive hyperventilation in this period. However, variation in control values, greater respiratory alkalosis and a secondary significant hyperventilation after 6-7 h of hypoxia in the domperidone treated animals prevents a clear conclusion as to the precise role of CB dopaminergic mechanisms in acclimatization to hypoxia. Nevertheless, peripheral DA receptor blockade with domperidone does alter the time course and magnitude of hyperventilation during the first 7 h of hypobaric hypoxia in goats.
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