A servo-control system for open- and closed-loop blood pressure regulation.

An electropneumatic servo-control system is described that can reduce and control arterial blood pressure in experimental animals. The device has been proved useful in the analysis of pressure-dependent physiological processes and allows the following two modes of operation: 1) a conventional open-loop setting that will reduce arterial pressure to a preselected set point and 2) a closed-loop mode that enables an adjustment to a dynamic pressure set point (i.e.

Diet and inflammatory bowel disease: a case-control study.

We conducted a population-based case-control study of inflammatory bowel disease and dietary habits in Stockholm during 1984-1987. We obtained retrospective information about food intake 5 years previously by a postal questionnaire for 152 cases with Crohn's disease, 145 cases with ulcerative colitis, and 305 controls. The relative risk of Crohn's disease was increased for subjects who had a high (55 gm or more per day) intake of sucrose (relative risk = 2.

Differential effect of neuropeptide-Y on membrane potential of cells in renal arterioles of the hydronephrotic mouse.

1. The effects of neuropeptide-Y (NPY) on the membrane potential of vascular smooth muscle cells were studied in renal arterioles of hydronephrotic mouse kidneys. 2.

Renovascular effects of neuropeptide-Y in the split hydronephrotic rat kidney: non-uniform pattern of vascular reactivity.

1. The renovascular effects of neuropeptide-Y (NPY) were examined in the split hydronephrotic rat kidney. 2.

Effects of neuropeptide-Y on renal function and its interaction with sympathetic stimulation in conscious dogs.

1. The effects of neuropeptide-Y (NPY) on renal function were investigated in conscious foxhounds. 2.

Importance of the stomach in maintaining calcium homoeostasis in the rat.

The stomach helps to maintain calcium homoeostasis by making dietary calcium accessible for uptake in the intestines, although the effect of the stomach on calcium homoeostasis is poorly understood. We examined the effect on blood calcium of gastric surgery in the rat. Within three weeks gastrectomy and fundectomy (excision of the acid producing part of the stomach) induced a slight lowering of the blood calcium concentration.

Thrombin and H64A subtilisin cleavage of fusion proteins for preparation of human recombinant parathyroid hormone.

Human parathyroid hormone, hPTH, an 84 amino acid polypeptide, was produced intracellularly in Escherichia coli as a fusion protein, linked to the C-terminus of a 15 kD IgG-binding protein. Approximately 100 mg fusion protein was obtained per liter fermentation medium. To test the efficiency of two alternative enzymatic cleavage methods, two fusion proteins differing only in the linker region were constructed.

Effects of gastrin on calcium homeostasis in chickens.

As in the rat, gastrin and an extract of the acid-producing part of the stomach (proventriculus) were found to lower the blood Ca2+ concentration in the chicken. Furthermore, gastrin enhanced the uptake of 45Ca into the femur. It has been suggested previously that gastrin causes hypocalcemia in the rat by releasing gastrocalcin, a hypothetical hormone thought to reside in the acid-producing part of the stomach.

Blood pressure control in arterial- and cardiopulmonary receptor denervated dogs.

The mechanisms influencing arterial blood pressure and heart rate were studied in conscious foxhounds after chronic sino-aortic and cardiopulmonary denervation (N = 6). In previous investigations it was shown, that this denervation produces hypertension and tachycardia, which is confirmed by the present study: Mean arterial blood pressure increased from 101 +/- 3 to 123 +/- 6 mmHg (P less than 0.05), and heart rate rose from 85 +/- 6 to 124 +/- 5 beats min-1 (P less than 0.

Canine hydrophobic surfactant polypeptide SP-C. A lipopeptide with one thioester-linked palmitoyl group.

The amino acid sequence and the posttranslational modification of the hydrophobic surfactant polypeptide SP-C from canine, rabbit and bovine lungs were established by direct sequence analysis and plasma-desorption time-of-flight mass spectrometry. The results reveal that canine SP-C has only one cysteine residue which, however, is palmitoylated, like the two Cys residues in other characterized SP-C molecules. In addition, canine SP-C is N-terminally truncated, with only 34 amino acid residues in its longest form.

Fetal and uteroplacental blood flow in prolonged pregnancies. A clinical study.

In a prospective study during 1 year, 102 women with prolonged pregnancies (more than 294 completed gestational days) were followed with serial pulsed Doppler blood flow examinations every 2nd day, either to spontaneous onset of labor (n = 82) or to induction of labor due to subsequently occurring complications (n = 20). Mean aortic blood velocity did not change significantly with gestational age beyond 294 days either in fetuses with normal outcome or in fetuses that developed asphyxia at birth. The flow velocity waveforms in the descending aorta, the umbilical artery, the common carotid artery and the uterine artery did not change significantly compared to the values at term.

Inflammatory bowel disease and tobacco smoke--a case-control study.

A case-control study was carried out in Stockholm, Sweden between 1984 and 1987 to evaluate the association of cigarette smoking and exposure to environmental tobacco smoke during childhood and the subsequent development of inflammatory bowel disease. Information on smoking was obtained by a postal questionnaire. The relative risk of Crohn's disease in current smokers compared with those who had never smoked was 1.

Identification of major slow blood pressure oscillations in conscious dogs.

All physiological feedback systems (e.g., in arterial pressure control) tend to oscillate in a characteristic manner.

Neurogenic control of pressure natriuresis in conscious dogs.

In this study we investigated the interaction of the sympathetic nervous system with renal perfusion pressure (RPP) in the short-term control of sodium excretion (UNa V). Pressure natriuresis curves (PNCs) were determined in 13 conscious dogs on a normal-salt diet during control conditions, bilateral common carotid occlusion (CCO), CCO combined with an intrarenal prazosin infusion, and during an intrarenal methoxamine infusion. RPP was reduced in controlled steps by inflation of a cuff placed around the renal artery.

Resetting of renal autoregulation in conscious dogs: angiotensin II and alpha1-adrenoceptors.

It has recently been shown, that common carotid occlusion (CCO) impairs autoregulation of renal blood flow (RBF) and glomerular filtration rate (GFR). This study was designed to investigate the mechanisms by which a moderate sympathetic stimulus influences RBF and GFR autoregulation. CCO provided a moderate sympathetic stimulus, and impaired autoregulation by increasing the lower autoregulatory limit of RBF and GFR by 21-30 mmHg.

Heterotopic new bone formation causes resorption of the inductive bone matrix.

The bone matrix of growing rats was labeled by multiple injections of 3H-proline, and demineralized bone matrix (DBM) was prepared. The DBM was allotransplanted heterotopically into growing rats. New bone formation was induced in and around the implants.

Retrospective versus original information on diet: implications for epidemiological studies.

The aim of this study was to evaluate the use of retrospective information on diet in relation to the information originally reported. Hospital controls (n = 131) who participated in a case-control study on diet and pancreatic cancer in Stockholm, Sweden, answered a second postal questionnaire four years later about their current and previous food consumption. The food consumption was dichotomized for the purpose of the analysis.

Elevated serum gastrin after food intake or acid blockade evokes hypocalcemia.

Gastrin lowers blood Ca2+ in the rat. Recently, it was suggested that gastrin causes hypocalcemia by releasing gastrocalcin, a hypothetical peptide hormone thought to reside in the acid-producing part of the stomach. The results of the present study suggest that not only exogenous gastrin but also gastrin of endogenous origin lowers blood Ca2+.

Hydrophobic surfactant-associated polypeptides: SP-C is a lipopeptide with two palmitoylated cysteine residues, whereas SP-B lacks covalently linked fatty acyl groups.

Pulmonary surfactant contains two hydrophobic polypeptides, SP-B and SP-C, with known amino acid sequences and with truncated subforms lacking the N-terminal residues. Treatment of SP-C with KOH releases fatty acids (palmitic acid to more than 85%) in molar ratios of 1.8-2.

Evidence that gastrin enhances 45Ca uptake into bone through release of a gastric hormone.

An acute challenge with gastrin-17 enhanced the uptake of 45Ca into sternum and several long bones in rats by about 10-30%; gastrectomy prevented this effect. Long-term treatment with (Leu15)-gastrin-17 (continuous infusion via osmotic minipumps for 4 weeks) enhanced the uptake of 45Ca into bone (examplified by radius and sternum) by 18-26% (tested on the last day of the infusion). Surgical removal of the acid-producing part of the stomach (fundectomy) or treatment with the anti-ulcer drugs, ranitidine (a histamine H2-receptor antagonist administered by continuous infusion) or omeprazole (an H+/K(+)-ATPase inhibitor administered daily by gastric tube for 4 weeks), induced sustained hypergastrinemia (through loss of acid feedback inhibition of gastrin release).

Factors affecting colectomy rate in ulcerative colitis: an epidemiologic study.

Factors affecting colectomy rate were studied in a retrospective population based series of 1586 patients with ulcerative colitis, in Stockholm County during 1955-84. Five hundred and sixty eight patients (36%) had total colitis at diagnosis, 603 patients (38%) left sided colitis, and 397 patients (25%) proctitis. During a median period of observation of 13 years 514 patients were treated by colectomy.

Sympathetic modulation of renal autoregulation by carotid occlusion in conscious dogs.

The effects of a moderate reflex activation of the sympathetic nervous system on renal blood flow (RBF) and glomerular filtration rate (GFR) were studied in 29 experiments on seven conscious foxhounds. Autoregulation parameters were derived by a stepwise reduction of renal artery pressure of 10-mmHg decrements. An occlusion of both common carotid arteries (CCO) was used as a moderate sympathetic stimulus.