In vivo release of interleukin-1 beta into hypothalamic extracellular fluid in rats: effects of repeated sampling

Interleukin-1 beta (Il-1 beta) concentrations in extracellular fluid (ECF) withdrawn at 10-min intervals through a push-pull cannula (PPC) located in the hypothalamus were studied in freely behaving male rats for 1 h at 24 and 72 h and again at 7 days after PPC implantation. Il-1 beta concentrations in ECF were similar in the latter. However, when ECF was sampled at 3 h and again 7 days after PPC implantation, Il-1 beta concentrations were greatly elevated at 7 days when compared to all other intervals. These results demonstrate how the relationships between Il-1 beta measured in ECF and the conditions of measurement appear to be integral parts of a whole intracerebral system: cytokine concentrations appear to be inextricably bound to intrahypothalamic conditions created by the sampling device presence and frequency of use.

Comparison of the number of vasopressin-producing hypothalamic neurons in rats and humans

The aim of this study was to assess the number and proportion of vasopressin-producing neurons in the hypothalamic magnocellular nuclei in rats and humans. Accurate and unbiased neuronal counts were estimated using the optical disector method. Arginine vasopressin-containing neurons were immunohistochemically visualized in formalin-fixed tissue sections. The magnocellular neurons were similar in size and morphology in both species. While the human hypothalamus contained significantly more vasopressin-containing neurons compared with the rat (36-fold increase), the proportion of vasopressin-containing neurons between species was similar. In both species, the majority of supraoptic neurons contained vasopressin, however the proportion of vasopressin-containing neurons in the human paraventricular nucleus was double that of the rat (nearly a 100-fold increase in number). These results suggest that the paraventricular nucleus contributes significantly to the release of vasopressin from the posterior pituitary in humans, whereas in rats vasopressin is mainly released by supraoptic neurons.

Drugs associated with drug-related deaths in Edinburgh and Glasgow, November 1990 to October 1992

Between 1991 and 1992 there was a four-fold increase in drug-related deaths in Glasgow. Comparing records of the drug-related deaths for November 1990-October 1991 and November 1991-October 1992 in Edinburgh and Glasgow, it was found that the increase in Glasgow was statistically significant and that heroin, often mixed with other drugs, which most often included temazepam, diazepam and alcohol, was implicated in the increase in deaths in Glasgow. A number of the deceased had been prescribed temazepam or diazepam. Discussed are the hazards of drug mixing and the possibility that the use of buprenorphine by drug injectors previously had kept the number of overdoses relatively low.

Drug abuse deaths in Glasgow in 1992--a retrospective study

A survey of 62 drug deaths in Glasgow showed a wider age range than expected (16-49), a high male to female ratio (44:18) and, where mode of employment had been recorded, a high degree of unemployment (91%). The majority of deaths occurred near centres of known supply. Although a number occurred in the family home, a large proportion were not at the place of residence. In only two cases was morphine detected alone. The majority of the deaths were from combinations of drugs, primarily with benzodiazepines.

[Aortic prosthetic endocarditis and periprosthetic abscess caused by Staphylococcus aureus]

Prosthetic endocarditis with annular abscess formation is a severe complication of cardiac valve replacement fortunately uncommon, though highly lethal. Increasing surgical experience and the high mortality with medical management have led to a widespread recommendation for early prosthetic replacement. We report a case of a 49 year old man with infective endocarditis due to Staphylococcus aureus in aortic ascendens prosthetic and aortic valve prosthetic complicated with periaortic abscess which was as successful treatment by drain of abscess without prosthetic replacement.

Sympathetic regulation in rabbits with heart failure: experience using power spectral analysis of heart rate variability

1. In five intact rabbits beta-adrenoreceptor blockade (i.v. propranolol), and combined cardiac blockade (i.v. propranolol plus i.v. methscopolamine sulphate) revealed that spectral power of heart rate (HR) variability at low frequencies (LF:0.0625-0.1875 Hz) was modulated predominantly by the sympathetic nervous system and power at high frequencies (HF:0.4373-0.5625 Hz) by vagal influences. 2. In 16 rabbits resting power of HR at LF and changes in LF power in response to maximal treadmill exercise were examined prior to and after 4 and 6 weeks of doxorubicin treatment (1 mg/kg twice weekly). 3. The development of doxorubicin-induced congestive heart failure (CHF) was accompanied by a progressive increase in resting LF power [control, 8.5 +/- 2.1; 4 weeks, 13.4 +/- 1.8; 6 weeks, 21.9 +/- 3.5 (beats/min)2, P < 0.005]. 4. Power spectral analysis (PSA) of HR variability in the immediate post-exercise period showed no change from resting values in normal rabbits [5.3 +/- 1.4 vs 8.5 +/- 2.1 (beats/min)2, P > 0.05] whereas CHF rabbits showed falls in LF power after 4 weeks [4.6 +/- 1.0 vs 13.4 +/- 1.8 (beats/min)2, P < 0.005] and 6 weeks [6.5 +/- 2.4 vs 21.9 +/- 3.5 (beats/min)2, P < 0.005] of doxorubicin treatment. 5. It was concluded that PSA of HR variability reflects the autonomic regulation of sinus node function in conscious rabbits. In doxorubicin-treated animals, the rise in LF power reflects increased sympathetic activity as CHF develops. However, the apparent paradoxical fall in LF power with exercise in these animals underscores the need for caution in interpretation of PSA profiles.

Delayed papillary muscle rupture following mild chest trauma

A case of delayed papillary muscle rupture is reported, which developed 24 hours following a mild chest trauma. Transthoracic echocardiography established the diagnosis; immediate mitral valve replacement was carried out. The postoperative course was uneventful.

The translocation, folding, assembly and redox-dependent degradation of secretory and membrane proteins in semi-permeabilized mammalian cells

We describe here a semi-permeabilized cell-system which reconstitutes the efficient synthesis, translocation, folding, assembly and degradation of membrane and secretory proteins. Cells grown in culture were treated with the detergent digitonin which selectively permeabilized the plasma membrane leaving the cellular organelles, such as the endoplasmic reticulum (ER) and trans-Golgi network intact. These permeabilized cells were added to an in vitro translation system, either wheatgerm or reticulocyte lysate, supplemented with RNA coding for either membrane or secretory proteins. Efficient translocation and modification of proteins by these cells was demonstrated by protease protection, photocross-linking of nascent chains to components of the translocation apparatus and by post-translational modifications such as glycosylation or hydroxylation. A comparison was made between the ability of semi-permeabilized cells and microsomal vesicles to fold and assemble proteins. The results show that the intact ER within these cells can assemble proteins much more efficiently than vesicularized ER. Furthermore, the semi-permeabilized cells carried out the redox-dependent degradation of tissue-type plasminogen activator. This system has all the advantages of conventional cell-free systems, including speed and, importantly, the ability to manipulate the components of the assay, while retaining intracellular organelles and, therefore, allowing cellular processes to occur as they would in the intact cell.

The Sec61 complex is essential for the insertion of proteins into the membrane of the endoplasmic reticulum

Cross-linking studies have implicated Sec61 alpha as the principal component adjacent to newly synthesised membrane proteins during insertion into the endoplasmic reticulum. Using proteoliposomes which have been reconstituted from purified components of the endoplasmic reticulum [Görlich, D and Rapoport, T.A., Cell 75 (1993) 615-630] we have found that the Sec61 complex, consisting of three subunits, is essential for the insertion of single-spanning membrane proteins. This is true for signal-anchor proteins of both orientations, and for proteins with a cleavable signal sequence. These results support the view that Sec61 alpha is a major component of the ER translocation site and promotes both the insertion of membrane proteins and the translocation of secretory proteins.

Variable tissue reactions and endocrine responses to a jugular catheter

Although the use of soft catheter materials allows for safe long-term venous access in humans and animals, a significant percentage of individuals react adversely. We have studied a group of 52 male rats over 30 days (d) for the category and degree of tissue responses to silicone-based catheters implanted in the jugular vein. Included in this evaluation was blood withdrawal at multiple intervals for assay of plasma hormones corticosterone (CORT) and prolactin (PRL) as they were correlated with the immune phenomena associated with early (5-7d) obstruction of the catheter tip. The intravascular portion of all catheters were covered with a transparent sheath which was composed of endothelial cells, smooth muscle cells, fibroblasts and numerous collagen fibers. Early blockage of catheters was the result of large white masses (wm) enclosing the tip which were continuous with the sheath. The wm consisted of: a) an inner zone nearest the catheter in some regions predominantly composed of numerous platelets and in others granulocytes and platelets; b) a middle zone containing numerous neutrophils; c) an outer zone containing a few inflammatory cells and many spaces filled with red blood cells. Rats that developed a wm blockage 7-10d after catheter placement had higher plasma CORT levels (3-5d post implant) when compared to those of animals with catheters remaining open 3-4 weeks. When viewed together, these observations describe a subset of a larger population of rats that have a local intravascular inflammatory reaction to silicone-based catheters. This preparation may be a useful model for investigating reported differences in human reactivity to silicone-based prostheses.

African-American factor VII-deficient variants in Georgia (FVII variants)

We studied African-American Factor (FVII)-deficient variants and carriers in Georgia by measuring their levels of FVII antigen (FVIIAG) and FVII procoagulant (FVIIC). Factor VIIAG was determined using enzyme-linked immunoassay (ELISA), whereas FVIIC was measured in two ways: 1) by fibrin clotting methods that employed human recombinant (HRFVIIC), human placental (HPFVIIC), rabbit brain (RBFVIIC), and bovine brain (BBFVIIC) thromboplastins; and 2) by an amidolytic method (AMFVIIC). Prothrombin time tests (PT) were also performed by standard methods. These 4 FVII-deficient patients and 3 carriers demonstrated the following results: PT: 18.2 +/- 6.5 sec; FVIIAG: 73.0 +/- 14.9%; HRFVIIC: 30.6 +/- 20.3%; HPFVIIC: 30.5 +/- 21.4%; RBFVIIC: 25.3 +/- 21.4%; BBFVIIC: 30.6 +/- 17.5%; AMFVIIC: 44.1 +/- 18.3%. We conclude that a group of clinically mild African-American FVII-deficient variants exists in Georgia. This group is characterized by the presence of FVIIAG and decreased FVIIC, using a variety of thromboplastins; and excellent correlation was noted for both human thromboplastins.

[The clinical and echocardiographic factors predictive of bioprosthetic leaflet rupture. The clinical tolerance for prosthetic malfunction]

OBJECTIVE

The objective of this research was to determine the existence of predictors of bioprosthetic valve disruption depending on the echocardiographic characteristic of the biologic prosthesis. It also determines the factors that provoke a need of emergency surgery and a bad clinical tolerance to the prosthetic dysfunction.

METHODS

Clinical and echocardiographic features of two groups of 28 and 21 patients, all of them carrying bioprosthesis, were compared. The groups were homogeneous in sex, age, location and durability of the prosthesis. The first group showed leaflet disruption in a period of 6 months to 1 year after the study, not in the second group. Calcification, thickness and mobility of leaflets, prosthetic function were studied. An echocardiographic score was given between 4 and 10 points. Left ventricular function and pulmonary pressure were also studied.

RESULTS

Valve thickness was statistically different in both groups (95% of the first group vs 71.3% of the second, p = 0.0281). There was no significant difference in calcification (52% vs 38.7%), nor in leaflet mobility (71.5% normal in the first group vs the 80% of the second group), nor in the prosthetic function (52.3% vs 76.6%, respectively). It was not found in the echocardiographic score either. Left ventricular function and pulmonary pressure were 91.6% and 55% normal respectively in the first group. They were 80% and 45.83% normal in the second group. Clinical onset of disruption was: 5 asymptomatic patients, 2 patients noticed a change in prosthetic click, 14 cases with progressive dyspnea, 6 patients with acute pulmonary edema and 1 patient with cardiopulmonary arrest and effective resuscitation. Symptoms were kept under control with medical treatment in 22 patients (78.55%) and 6 patients were referred to surgery. These latter suffered from pulmonary hypertension and two of them had left ventricular dysfunction. Surgical mortality was 3% (1 patient).

CONCLUSIONS

No echocardiographic features were found as being predictors of imminent bioprosthetic disruption. However, leaflet thickness is the most common finding. Symptoms of disruption in patients without high surgical risk factors (left ventricular dysfunction or pulmonary hypertension) are kept under control with medical treatment. Therefore, "prophylactic" surgery is not needed in bioprosthesis with signs of degeneration and normal hemodynamic performance.

ANP binding sites are increased in choroid plexus of SLS-1 rats after 9 days of spaceflight

Specific alpha-rat 28-amino acid atrial natriuretic peptide [ANP(99-126)] (rANP) binding sites in choroid plexus and meningia of rats flown for 9 days on the mission STS-40 (SLS-1) carried on the space shuttle Columbia in June 1991 were analyzed after incubation of brain sections with 125I-rANP and autoradiography, using computer-assisted microdensitometric image analysis. The number of 125I-rANP binding sites (expressed by Bmax values) in the choroid plexus of lateral and third ventricles of these rats was significantly increased (x 1.5-2.5 times), as compared with that found in ground control rats. No differences in the binding affinity (deducible from Kd values) were observed at the level of these structures. The choroid plexus from the fourth ventricle of the same rats displayed no changes in the binding capacity or affinity after the spaceflight. Meningia from the rats flown in space did not demonstrate any significant modifications of the number of 125I-rANP binding sites, but displayed a significant increase in Kd values, which suggested a reduced affinity of the meningeal ANP receptors during a 9-d spaceflight. The possibility that atrial natriuretic peptide may be involved in the regulation of fluid and electrolyte fluxes in the brain, during adaptation to microgravity, through modified expression of specific high affinity receptors, mainly in choroid plexus from forebrain or in meningia, must be considered.

Cellular and molecular abnormalities in the vascular endothelium of diabetes mellitus

Diabetic vascular complications affect both micro- and macrovasculature, primarily in the retina, renal glomeruli, and multiple sites in the macrovessels. This review presents a summary of the abnormal function found in vivo and in cultured vascular cells exposed to elevated levels of glucose. We also discuss the various biochemical hypotheses that have been proposed to explain the adverse effects of hyperglycemia on vascular cells.

Cardiac and plasma atrial natriuretic peptide after 9-day hindlimb suspension in rats

To determine atrial natriuretic peptide (ANP) adaptation to simulated weightlessness, immunoreactive plasma (ir-NH2- and ir-COOH-terminals) and atrial (ir-COOH-terminal) ANP levels, atrial mRNA expression, immunoreactive cardiocyte ANP levels (ir-NH2- and ir-COOH-terminals), and ultrastructural observations of granules in atrial cardiocytes were assessed in male Wistar rats after a 9-day hindlimb suspension. Plasma ir-NH2- and ir-COOH-terminal ANP concentrations decreased by 17 (P < 0.05) and 37% (P < 0.05), respectively, in suspended rats. A concomitant ir-COOH-terminal ANP content reduction was also observed in left (31%; P < 0.01) and right atria (25%; P < 0.05). Atrial ANP mRNA expression was severely depleted in the right atrium and less so in the left atrium after 9 days of hindlimb suspension. Immunocytochemistry observations demonstrated lowered NH2- and COOH-terminal ANP immunoreactivities in left and right atria from suspended rats. A reduced number of storage granules (dense granules) in both atria was also noted on ultrastructural analysis. It was concluded that ANP biosynthesis, storage, and release were decreased after a 9-day hindlimb suspension.

[Monocytoid lymphoma evolving into large-cell lymphoma]

Monocytoid B cell lymphoma (MBCL) is a newly recognized low-grade lymphoma. The malignant cells of MBCL seems to be the counterpart of reactive monocytoid B cells. The MBCL cells show a resemblance to the cells of hairy cell leukemia (HCL). The cell of MBCL exhibits immunoglobulin light chain restriction and markers of terminal BG cell differentiation. On the other hand, the HCL lack expression of CD 25 and are tartrate resistant, acid phosphatase-negative. The MBCL has prediction for elderly females. At the time of diagnosis, it is usually present in stage I or II. It may be difficult to differentiate the clinical and morphological expression of MBCL from that of any other indolent lymphoproliferative diseases, especially HCL and small lymphocytic lymphoma. Unlike other low grade lymphomas in MBCL, however, splenomegaly and bone marrow involvement are uncommon, while leukemic conversion is very rare. The MBCL transformation or association to high grade lymphomas is very unusual. In this case, it isn't clear if MBCL undergoes progression to higher grade lymphomas or if there is a "composite lymphoma" at the onset, in any case the prognosis is worse. In our patient, the involvement seemed to be only at the spleen and caeliac nodes, there was not bone marrow involvement. The fast evolution suggests that the MBCL underwent a transformation to a higher grade lymphoma. It is a common behavior in the low grade lymphoma.

Thymosin beta 4 synergizes with human granulocyte-macrophage colony-stimulating factor in maintaining bone marrow proliferation

Recent evidence supports a role for thymosin beta 4 (T beta 4) in the inhibition of murine hematopoietic stem cell proliferation. This supposition results from studies in which the N-terminal tetrapeptide derived from native T beta 4 was administered to mice and appeared to prevent CFU-S recruitment into DNA synthesis. The importance of this observation was the concomitant ability of the tetrapeptide to prevent cytosine arabinoside (ara-C) toxicity in mice given LD50 doses of this drug. In the present study, we have extended these observations by demonstrating that whole synthetic T beta 4 is more effective than the N-terminal tetrapeptide in protecting mice from the toxicity of ara-C. This observation supports the hypothesis that T beta 4 is the biologically important parent molecule for this activity. To determine if inhibition of cell cycle progression also occurs in committed human bone marrow progenitors treated with T beta 4, we have investigated the effects of synthetic T beta 4 on proliferating and unstimulated enriched human bone marrow. In short-term liquid cultures studied sequentially over 1-7 days, T beta 4 failed to inhibit cell proliferation, but maintained the proliferative effect of granulocyte-macrophage colony stimulating factor (GM-CSF) on days following maximum stimulation (days 5-7). No effect was noted before the fifth day in culture, nor did T beta 4 exert any demonstrable effect in the absence of added GM-CSF. Any observable effect of T beta 4 required that it be present in the cultures on or before day 3 of GM-CSF stimulation. These results suggest that an additional effect of T beta 4 is the stimulation of a subpopulation of committed human bone marrow precursor cells to become more sensitive to the growth-promoting activity of GM-CSF, thereby enhancing myelopoiesis. It is of interest that the N-terminal peptide of T beta 4 is a shared sequence with tumor necrosis factor alpha, which is also known to have a similar stimulatory capacity. We, therefore, postulate that the growth enhancement noted in short-term cultures is mediated by the region containing these shared sequences.

Localized pleural microdeposition of type A amyloid in a patient with rheumatoid pleuritis. Histologic distinction from pleural involvement in systemic amyloidosis

Decorticated pleural tissue from a 74-year-old man with rheumatoid arthritis, an exudative pleural effusion, and normal left ventricular function contained microscopic deposits of amyloid A protein, localized to the interface between a deep layer of dense fibrocollagen and a layer of granulation tissue beneath a surface fibrin exudate. Previously reported instances of pleural amyloid deposition have occurred in patients with presumed systemic amyloidosis, and most such effusions are the result of congestive heart failure. This patient had no evidence of systemic amyloidosis, and this case appeared to be an example of an unusual form of localized amyloidosis, so-called periinflammatory amyloidosis A. These observations suggest that amyloid in a pleural biopsy should not be construed per se to be diagnostic of systemic amyloidosis.

Effects of angiotensin II receptor blockade on remnant glomerular permselectivity

This study examined the mechanisms by which angiotensin II (Ang II) receptor blockade improves glomerular barrier function in rats with reduced nephron number. Proteinuria was measured at four weeks after 5/6 renal ablation, and rats were then divided into a group which received the Ang II receptor blocker MK954 and a group which received no treatment. Studies performed one week later showed that Ang II receptor blockade reduced proteinuria without altering GFR in renal ablated rats. Micropuncture studies showed that Ang II blockade reduced both mean arterial pressure (142 +/- 7 mm Hg, ablation without treatment; 105 +/- 2 mm Hg, ablation with treatment) and glomerular transcapillary pressure (54 +/- 3 mm Hg, ablation without treatment; 43 +/- 1 mm Hg, ablation with treatment). Dextran sieving studies showed that untreated rats developed a size-selective defect characterized by increased transglomerular passage of neutral dextrans with radii 54 to 76 A and a charge-selective defect characterized by an increased transglomerular passage of anionic dextran sulfate with a radius of approximately 18 A. Ang II blockade reduced fractional clearance values for large neutral dextrans near to values observed in normal rats but had no effect on the fractional clearance of dextran sulfate (0.68 +/- 0.11, ablation without treatment; 0.66 +/- 0.08, ablation with treatment; 0.46 +/- 0.05, normal rats). These findings indicate that reducing Ang II activity improves size-selectivity without affecting charge-selectivity in injured remnant glomeruli.