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Biomedical subjects

J Christensen

Publications and source records attributed to J Christensen.

At least 145 records · Page 8Linked to original sources
PubMed1992

The consequences for renal function of widening of the interstitium and changes in the tubular epithelium of the renal cortex and outer medulla in various renal diseases.

The following parameters were measured in 63 renal biopsy specimens, most of which exhibited mesangioproliferative glomerulonephritis: the relative area of the interstitium and the area of the capillaries in the cortex and outer stripe of the outer medulla, and the area of the epithelium of the proximal tubules and of the ascending limbs of Henle's loop. The percentage of hyalinized glomeruli was also determined. Investigation of correlations between these values and parameters of renal function revealed the following: 1) The serum creatinine concentration increases and the endogenous creatinine clearance decreases significantly as the interstitium of both the cortex and the outer stripe of the outer medulla increases in width. 2) The urine osmolality decreases significantly as the epithelial areas of the proximal tubules and ascending limbs of Henle's loop decrease, and as the serum creatinine concentration rises and the areas of the interstitium increase. 3) No significant correlation exists between the percentage of hyalinized glomeruli and the urine osmolality. 4) The total area of the intertubular capillaries in the cortex decreases significantly as the interstitium in this area increases in width and as the serum creatinine concentration increases. 5) Compensatory hypertrophy of individual nephrons, as proposed by Bricker's hypothesis, was found only where more than 90% of the glomeruli were hyalinized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Risk of cervical intraepithelial neoplasia in women with glomerulonephritis.

OBJECTIVE: To investigate the occurrence of cervical intraepithelial neoplasia in women with glomerulonephritis and its possible association with immunosuppressive treatment. DESIGN: Retrospective study of cytological or histological specimens from women presenting with glomerulonephritis and a group of case and age matched controls. SETTING: University department of pathology, Norway. PATIENTS: 81 women presenting with glomerulonephritis from 1981 to 1988, from whom gynaecological cytological or histological specimens were available. A group of 162 case and age matched controls. MAIN OUTCOME MEASURES: Age when glomerulonephritis of cervical intraepithelial neoplasia was diagnosed, type and characteristics of kidney lesion, stage of cervical intraepithelial neoplasia and presence of human papillomavirus, use of immunosuppressive treatment. RESULTS: Cervical intraepithelial neoplasia was more common in women with glomerulonephritis than in their controls (16/81 (20%) v 7/162 (4%), p less than 0.001) and was more advanced in those with glomerulonephritis than in the controls (9/81 (11%) of the study group had grade III cervical intraepithelial neoplasia compared with 1/162 (1%) of the controls). The increased occurrence of cervical lesions was independent of the use of immunosuppressive treatment, but the individual lesions tended to be more advanced when it was used (four of the seven cervical lesions in women with glomerulonephritis who had received immunosuppressive treatment were carcinoma in situ). Of the nine cervical lesions tested, seven were virus associated. CONCLUSION: Women with glomerulonephritis should have regular cervical smears, irrespective of their use of immunosuppressive treatment.

Adult↗
PubMed1991

Paradoxical relationship between substrates and agonist-induced contractions of opossum esophageal body and sphincter in vitro.

Possible differences in the abilities of esophageal body and lower esophageal sphincter muscles to utilize substrates to support agonist-induced contractions were studied. Strips of longitudinal, circular, and lower esophageal sphincter muscle from the opossum esophagus were first contracted to approximately 70% of the maximal contraction elicited by acetylcholine, histamine, or substance P. The tissues were then exhausted by exposure to 5 x 10(-4) M carbachol and a 15% O2-5% CO2-80% N2 gas mixture for 90 min. They were next reequilibrated with one of a number of alternative substrates and 95% O2-5% CO2 for 3 hr. Responses to the initial agonist doses were again noted and compared to controls. The alternative substrates were: 2-deoxyglucose, glucose, fructose 1-6 diphosphate, pyruvate, lactate, acetate, butyrate, caprylate, histidine, leucine, aspartate, alanine, succinate, acetoacetone, and beta-hydroxybutyrate. The results obtained show qualitative differences in the ability of the three muscle types to use these substrates. More importantly, however, the ability of any one substrate to support contractions was a function of the agonist used to stimulate the muscle. The evidence suggests, therefore, that not all pharmacologic receptors have equal access to intracellular energy sources.

Acetylcholine↗
PubMed1991

The distribution of myelinated nerve fibers in the mature opossum esophagus.

Myelination of nerve fibers could be important in establishing normal esophageal peristalsis. We therefore examined the general distribution and the age of appearance of myelinated nerve fibers in the smooth-muscle part of the esophagus of the American opossum. Tissues stained with thionein and Sudan black B were examined by light microscopy. Other tissues were prepared for electron microscopy and examined in the light microscope in Toluidine blue stained sections as well as at electron microscopy. In mature animals (weight greater than 2.0 kg, age greater than or equal to 1 year), myelinated nerve fibers, oriented mainly craniocaudally, were most abundant at the striated muscle-smooth muscle junction, and declined in density distally along the organ. They were nearly absent at the esophagogastric junction. They were more abundant in the stomach just below the esophagogastric junction. The myelinated nerve fibers commonly lay within sheathed fascicles that had the appearance of peripheral nerves, like the shunt fascicles of the stomach and colon. In immature animals myelinated fibers did not appear until a weight of about 1 kg was reached, 50 days after weaning and about 150 days after birth. Since the younger animals are presumably swallowing normally, myelination of the extrinsic nerves is not essential for esophageal motor function.

Animals↗
PubMed1991

Atrial natriuretic peptide concentrations in umbilical cord plasma from pre-eclamptic women.

Atrial natriuretic peptide (ANP) was measured in arterial and venous umbilical cord plasma at the time of delivery by cesarean section in pre-eclamptic (n = 7) and normal women (n = 6). In addition venous samples were obtained from pre-eclamptic (n = 7) and normal pregnant women (n = 7) near term. ANP plasma levels were higher in pregnant women with pre-eclampsia than in normal pregnant women (27.9 +/- 4.4 [mean +/- SEM] and 14.1 +/- 2.5 pmol l-1, respectively, P less than 0.05). Immediately after delivery plasma ANP in pre-eclamptic mothers was 66.7 +/- 12.8 pmol l-1 compared to 13.9 +/- 2.2 pmol l-1 in normal mothers (P less than 0.01). However, in the pre-eclamptic group the levels of ANP in arterial and venous umbilical cord plasma (19.5 +/- 4.2 and 16.7 +/- 4.3 pmol l-1, respectively) were significantly (P less than 0.01) lower than ANP levels in arterial and venous cord plasma (39.6 +/- 1.0 and 31.1 +/- 4.2 pmol l-1, respectively) from normal mothers. It is concluded that the increased ANP plasma level in pre-eclamptic women originates from a maternal source. In addition, since the ANP level is lower in cord plasma than in maternal plasma in pre-eclampsia, feto-placental volume homeostasis may also be changed in pre-eclampsia.

Adult↗
PubMed1990

Quantitative measurement of Fc receptor activity on human peripheral blood monocytes and the monocyte-like cell line, U937, by laser flow cytometry.

The expression of high affinity Fc receptors for IgG (FcRI) on the cell line U937 has been measured by flow cytometry, using fluorescein isothiocyanate-conjugated human IgG (FITC-IgG) calibrated spectrofluorimetrically against lasergrade fluorescein (Fl). A standard curve is presented, relating the effective fluorescence in terms of fluorescein equivalents per IgG molecule, to the degree of conjugation of FITC-IgG. The flow cytometer was calibrated with commercially available fluorescein-coupled latex beads. The quantitation of FcRI, in terms of sites per cell and affinity constants, was compared with a radioligand assay performed concurrently on the same cell population. Good agreement between the two assays was observed. The Fc receptors on peripheral blood monocytes were measured in unpurified lysed blood by gating on forward/side scatter. Monomer IgG binding to monocyte FcRII or FcRIII cannot be measured in direct IgG radioligand analyses because of the low affinity of these receptors and their low numbers per cell. However, flow cytometry may be employed for measuring both high and low affinity ligand-FcR interactions, using monomer FITC-IgG.

Antigens, Differentiation↗
PubMed1990

Acute renal failure in man: new aspects concerning pathogenesis. A morphometric study.

The morphometric investigation of the proximal and distal tubules, the cortical interstitium, the intertubular capillaries, the renal corpuscles and the juxtaglomerular apparatuses (JGAs) in 56 cases in the oligoanuric, polyuric, and normuric phases of human acute renal failure (ARF), 6 cases of myeloma kidney with clinically confirmed ARF and 21 control kidneys revealed the following: (1) The main pathological change in human ARF is swelling of the epithelial cells of the proximal and distal tubules. Necrosis of these cells was observed in some cases but usually only as single cell necroses. (2) The interstitium of the cortex and of the outer stripe of the outer medulla is significantly widened in most cases of ARF. (3) In proximal tubules proximal to occluding casts (which were observed only in the plasmacytoma cases), the lumina are not widened but are narrower than normal, and the cross-sectional area of the epithelium is not greater but smaller than normal. (4) The JGAs were significantly larger in kidneys in the oligoanuric phase of ARF (with 1 exception) than in normal kidneys. In the normuric and polyuric phases they were slightly (not significantly) smaller than normal. In myeloma kidneys with occluding casts and/or diffuse interstitial fibrosis, the JGAs were significantly smaller than normal. From these findings it is concluded that: (1) The fall in glomerular filtration rate (GFR) in the postshock phase of ARF is not caused by nonselective back-diffusion of the primary urine through necrotic tubules or by compression of the lumina of the proximal and distal tubules by interstitial edema. A fall in GFR associated with occluding casts in the distal tubules is found only in the myeloma kidney and does not lead to widening of the proximal tubules but to tubular atrophy and narrowing of the lumen. (2) The casts seen in the lumina of the ascending limb of Henle's loop in some cases of ARF, which consist of hemoglobin, Tamm-Horsfall protein or desquamated blebs, do not occlude the lumen, since they are not associated with atrophy or luminal dilatation of the proximal tubules. (3) The JGAs with their secretory product renin-angiotensin II, together with adenosine, which is released in kidneys with ischemic or toxic damage, play a critical role in the pathogenesis of ARF. (4) In myeloma kidneys with ARF, in which the JGAs are markedly atrophic, the potentiated effect of adenosine that has been observed with a chronic absence of urine flow probably leads to a progressive, irreversible drop in GFR associated with tubular atrophy.

ADP-Ribosylation Factor 6↗
PubMed1989

[Anterior gastropexy using the Boerma method in gastroesophageal reflux].

The results obtained in 38 patients with gastro-oesophageal reflux who had been submitted to operation by Boerema's method are presented. Twenty-nine (76%) became entirely symptomfree and eight (21%) experienced reduction of symptoms. Postoperative oesophageal stenosis was demonstrated in five patients.

Adolescent↗
PubMed1989

[Readmitted patients at a medical ward. 1. Health conditions].

The object of this investigation was to describe the health and social-medical conditions of readmitted patients and to assess which of these conditions was the main reason for readmission. A total of 166 patients (with an average age of 73 years) readmitted to the ward within three months of the last discharge from the ward were interviewed about their health, social and housing conditions in the period prior to admission. In this first report from the investigation it was found that 57% were readmitted within one month. 71% stated that they had experienced symptoms from the heart and/or respiratory system and 52% had experienced symptoms from the locomotor system. Only 13% did not receive any daily prescription drugs. Approximately 1/3 considered their health to be good and 1/3 poor, respectively. These results were compared with the data available in the literature about the health conditions of non-hospitalized elderly persons. It was demonstrated that the readmitted patients had more health complaints, a more extensive medication and considered their health worse.

Adult↗
PubMed1989

[Readmitted patients at a medical ward. 2. Social and housing conditions].

The object of this investigation was to describe the health and social medical conditions of elderly readmitted patients and to assess which of these conditions was the main reason for readmission. A total of 166 patients (with an average age of 73 years) who were readmitted to the ward within three months of the previous discharge were interviewed about their health, social and housing conditions during the period prior to admission. The interviews were conducted in the second half of 1987. In this second report from the investigation it was found that 84% lived in flats with good facilities. 50% lived alone, 57% received at least one form of public assistance (ie home help, home nursing etc.). The interviewers considered that social and housing conditions were the only reason for 12% of the readmissions and were contributory causes in 15% of the readmissions. It is concluded that health reasons were the primary reasons for the present readmission.

Aged↗
PubMed1989

Distribution of immunoreactive substance P in opossum esophagus.

We localized immunoreactive substance P and measured its content throughout the opossum esophagus. Substance P-like immunoreactive nerve fibers were more abundant in muscularis mucosae than in the longitudinal smooth muscle layer and more abundant in the latter than in the circular smooth muscle layer. The distribution of substance P-like immunoreactive nerve fibers in the circular muscle layer of the esophagogastric junction was comparable to that of the esophageal body. Immunoreactive fibers were also found on and in arteries, submucosal glands, and epithelium, but none were seen in striated muscle. Both the myenteric and submucous plexuses contained substance P-like immunoreactive nerve cell bodies and processes. In the muscularis propria, the content of substance P-like immunoreactive peptide (pg/mg protein, means +/- 1 SE) in the smooth muscle region of the esophageal body (5.9 +/- 0.6) exceeded that in the striated muscle region (2.5 +/- 0.2) and at the esophagogastric junction (1.8 +/- 0.5), but the latter two values were similar (P less than 0.05). Mucosal content of substance P in the region of the esophagogastric junction (1.2 +/- 0.1) differed from that of the smooth muscle region of the esophageal body (9.2 +/- 2.6) but not (P greater than 0.05) from that of the striated-muscle region (5.9 +/- 1.0). The broad distribution and diversity of immunoreactive structures suggest that substance P may have both sensory and motor functions in the esophagus.

Animals↗
PubMed1989

Immunotherapy with dog and cat extracts in children.

Hypersensitivity to dogs and cats causes asthma in many children. In this open controlled clinical study we wanted to establish whether immunotherapy can be recommended as a supplement to conventional medical therapy in dog- and cat-induced asthma in children. Twenty-seven children with mean age 10 7/12 years and with allergy to dog or cat according to anamnesis, skin prick test (SPT), specific IgE (RAST) and bronchial provocation test (BPT) entered the study. On the basis of age and bronchial sensitivity they were randomly allocated to either immunotherapy with dog or cat extract (active group, n = 14) or conventional medical therapy (control group, n = 13). Immunotherapy comprised subcutaneous injections with an alum-adsorbed depot extract (Alutard-SQ), and a maintenance dose of 100,000 SQ-U or the maximum tolerated dose. Before entering the study and after 9 months' therapy the patients were evaluated by BPT, SPT, RAST - and IgG4 analyses. The active group showed statistically significant change in bronchial tolerance (P less than 0.02), whereas no such change was found in the control group (P greater than 0.05). The change in skin sensitivity was significantly greater in the active group than in the control group (P less than 0.05), whereas no significant differences were found in RAST and IgG4. However, a significant (P = 0.05) increase in IgG4 was seen in the active but not in the control group. Frequency and degree of side effects in this study were acceptable.

Adolescent↗
PubMed1989

Intramural neural control of opossum sphincter of Oddi.

We evaluated the intramural neural control of the opossum sphincter of Oddi (SO) in an in vitro preparation. Force transducers were used to record contractions at four sites along the sphincter segment. To stimulate intramural nerves, 10- to 120-s trains of pulses (4-10 V amplitude, 0.5 ms duration, and 5 Hz frequency) were delivered to one of three electrode pairs implanted along the SO. Electrical stimulation in the proximal, mid, or distal SO elicited phasic contractions that invariably originated in the proximal SO and propagated antegrade along the entire length of the sphincter segment. Stimulus-evoked contractions resembled spontaneous antegrade peristaltic contractions, but occurred at a higher rate (12-20/min). Atropine completely blocked this excitatory response to nerve stimulation. After atropine, nerve stimulation in the proximal, mid, or distal SO abolished spontaneous contractions at and distal to the site of stimulation for the duration of the stimulus. The inhibitory response to nerve stimulation was completely blocked by tetrodotoxin but was unaffected by phenoxybenzamine, tolazoline, or propranolol. We conclude that 1) the opossum SO is innervated by intramural cholinergic excitatory nerves and nonadrenergic noncholinergic inhibitory nerves; 2) cholinergic excitatory nerves are organized in ascending neural pathways, whereas nonadrenergic noncholinergic inhibitory nerves descend along the length of the SO; and 3) these neural pathways may modulate SO peristalsis in vivo and participate in ascending excitatory and descending inhibitory reflexes.

Ampulla of Vater↗