Heat acclimation and hypohydration: involvement of central angiotensin II receptors in thermoregulation

This investigation attempted to confirm the involvement of central ANG II-ergic signals in thermoregulation. Experiments were conducted on rats undergoing short (STHA)- and long (LTHA)-term heat acclimation, with and without superimposed hypohydration. Vasodilatation (VTsh) and salivation (STsh) temperature thresholds, tail blood flow, and heat endurance were measured in conscious rats during heat stress (40 degrees C) before and after losartan (Los), an ANG II AT(1)-selective receptor antagonist, administration either to the lateral ventricle or intravenously. Heat acclimation alone resulted in decreased VTsh. STsh decreased during STHA and resumed the preacclimation value, together with markedly increased heat endurance on LTHA. Hypohydration did not affect this biphasic response, although STsh was elevated in all groups. The enhanced heat endurance attained by LTHA was blunted. Neither Los treatment affected the nonacclimated rats. In the heat-acclimated, euhydrated rats, intracerebroventricular Los resulted in decreased VTsh, whereas intravenous Los resulted in elevated STsh. Both intracerebroventricular and intravenous Los led to markedly enhanced heat endurance of the LTHA hypohydrated rats. It is concluded that the LTHA group showed a loss of the benefits acquired by acclimation on hypohydration, whereas the STHA rats, which show an accelerated autonomic excitability in that phase, gained some benefit. It is suggested that ANG II modulates thermoregulation in conditions of chronic adjustments. Central ANG II signals may lead to VTsh upshift, whereas circumventricular structures, activated via circulating ANG II, decrease STsh. On hypohydration these responses seem to be desensitized.

[Femoral neck fracture complicating algodystrophy in pregnancy]

BACKGROUND

Sympathetic reflex dystrophy is an uncommon cause of pelvic pain not to be overlooked in pregnant women.

CASE REPORT

At 8 months pregnancy, a 27-year-old woman complained of invalidating pain of the left hip. Magnetic resonance imaging of the pelvis performed the day after delivery evidenced a non-displaced fracture of the femoral neck and a typical aspect of sympathetic reflex dystrophy.

DISCUSSION

The true frequency of sympathetic reflex dystrophy during pregnancy is probably underestimated. Approximately one hundred cases have been reported. The hip joint is involved in 9 out of 10 cases. Such localizations are uncommon outside pregnancy, accounting for 14 to 17% of all cases.

Neuronal actions of oxytocin on the subfornical organ of male rats

The aim of this study was to investigate effects of oxytocin (OT) on electrical neuronal activities in rat subfornical organ (SFO) and compare its action with the well-described excitatory effects of blood-borne angiotensin II (ANG II) on the same SFO neurons. With the use of extracellular recordings from spontaneously active neurons in slice preparations of the SFO of male rats, 11.7% of tested neurons (n = 206) were excited and 9.7% were inhibited by superfusion with 10(-6) M OT. Both excitatory and inhibitory effects of OT were dose dependent with similar threshold concentrations and were blocked by a specific OT-receptor antagonist but not by a vasopressin receptor antagonist. Blocking synaptic transmission with low calcium medium suppressed only inhibitory effects of OT. All but one of the OT-sensitive neurons were also excited by superfusion with ANG II at a concentration much lower than required for OT, suggesting that synaptically released OT rather than blood-borne OT alters the activity of SFO neurons in vivo. The results support the hypothesis that neurally released OT may modulate SFO-mediated functions by acting on OT-sensitive neurons.

Surface corrosion of dental ceramics in vitro

The objective of this study was to evaluate possible structural surface changes in different dental ceramic materials in a provocative corrosive environment in vitro. On the basis of compositional and microstructural differences, seven dental ceramic materials were selected for the test. After sintering and autoglazing, the surface roughness of the specimens was evaluated by confocal laser profilometry. A specially designed specimen holder made it possible to locate the same surface area before and after contact with the corrosive solution. The surface topography was additionally analysed using scanning electron microscopy. All the ceramic materials displayed evidence of surface structural changes on the exposed surfaces, but to varying degrees. Traditional leucite-containing feldspathic porcelains displayed an increase in surface roughness compared with baseline conditions when kept in 4% acetic acid at 80 degrees C for 18 h. Micro-crystalline and non-crystalline ceramic materials, on the other hand, demonstrated a smoother surface or just a minor increase in surface roughness. Whether or not the smoother post-corrosion appearance of certain ceramic materials is indicative of a true increase in corrosion resistance or is merely the result of an uniformly progressive corrosive process will be the object of future studies.

[Status of problems with administration of hormonal contraceptives]

Following the application of oral hormonal contraceptives situations may occur which need fast clarification. In this report we discuss the practical aspects of forgetting to take hormonal contraceptives, the risk for birth defects, the time when to restart taking oral contraceptives after delivery and abortion, the indications for stopping the application, the taking of oral contraceptives under anticoagulant therapy, the behaviour during migraine, the raising need of ethinylestradiol in the case of epilepsy, the procedure in case of oligophrenia, the prevention of the rheumatoid arthritis as well as special questions in cases of diabetes mellitus and gestational diabetes.

National oral health survey Zimbabwe 1995: dental caries situation

Ten years after completion of the first national oral health survey, the second such survey was carried out in 1995. Application of a multi-stage sampling procedure resulted in 3,709 persons being examined according to the WHO oral health assessment form and criteria. The background variables studied were age, gender, type of location, socio-economic status. Comparison with results from major studies in other African nations are presented. It was concluded that the prevalence of dental caries in all age groups was high but that the severity was low. The prevalence of unmet treatment needs was very high with extraction as the predominant mode of treatment. The survey has shown that the vast majority of Zimbabweans are not receiving and/or are not seeking oral care.

National oral health survey Zimbabwe 1995: periodontal conditions

Ten years after completion of the first national oral health survey, a second national oral health survey was carried out in 1995. Application of a multi-stage sampling procedure resulted in 3,709 persons being examined. WHO's oral health assessment form and CPITN index was used. The background variables studied were age (15-19, and 35-44-year olds), gender, type of location, socio-economic status and level of education. Results suggest that the periodontal health of adolescents was better in 1985 than in 1995. Overall, the prevalence of periodontal conditions in both age groups was high but its severity was low. The need for complex periodontal treatment was only 4 per cent for adults. The survey has shown that the vast majority of Zimbabweans are not receiving and/or are not seeking periodontal care.

Nitric oxide as a peripheral and central mediator in temperature regulation

In animals including humans nitric oxide (NO) serves as a biological messenger both peripherally at neuroeffector junctions and in the central nervous system where it modulates neuronal activity. Evidence for the involvement of NO in homeostatic control is accumulating also for temperature regulation in homeotherms. In the periphery an auxiliary role in the vasomotor control of convective heat transfer to heat dissipating surfaces and modulation of thermoregulatory heat generation, especially in brown adipose tissue as the site of nonshivering thermogenesis, are discussed as NO actions. At the central level a thermolytic role of NO in thermoregulation as well as in fever is assumed, however, experimental data opposing this view suggest that topical specificity may be important. At the level of single neurons, the observed interrelationships between thermosensitivity and responsiveness to NO are still not consistent enough to reconcile these data with the effects of NO-donors and inhibitors of NO-synthase on temperature regulation.

Energy restriction with high-fat diet enriched with coconut oil gives higher UCP1 and lower white fat in rats

OBJECTIVE

To investigate the effects of overfeeding on a high fat diet, enriched in coconut oil, and the influence of food restriction on the uncoupling protein (UCP1) expression and on body fat content.

DESIGN AND SUBJECTS

In experiment I, female Wistar rats were fed ad libitum either a normal-fat diet (control group, C) or a high-fat diet (HF), enriched in coconut oil, for 7 weeks. In experiment II, HF rats after finishing experiment I were fed (for 3 weeks) either the normal-fat diet (group CAHF, Control After High Fat) or food restricted diets which provided 60% of the energy intake of group CAHF: a group fed a low-energy, normal-fat diet (LENF) and another fed a low-energy, high-fat diet (LEHF).

MEASUREMENTS

Body and fatty depot weights. Food intake. Protein and UCP1 levels of interscapular brown adipose tissue.

RESULTS

High-fat diet feeding promoted an increase in body fat content, body weight and UCP1 levels. Energy restriction induced similar body weight reduction in groups LENF and LEHF. However, some adipose depots were more strongly reduced in the rats fed the high-fat diet enriched in coconut oil (group LEHF) than in the rats fed the normal-fat diet (Group LENF). Specific UCP1 was 2.0 (group LENF) and 3.4 (group LEHF) times higher than in controls (group CAHF).

CONCLUSION

The coconut-oil enriched diet is effective in stimulating UCP1 expression during ad libitum feeding and in preventing its down regulation during food restriction, and this goes hand in hand with a decrease of the white fat stores.

Myeloma light chains are ligands for cubilin (gp280)

Although myeloma light chains are known to undergo receptor-mediated endocytosis in the kidney, the molecular identity of the receptor has not been characterized. We examined the interaction between cubilin (gp280) and four species of light chains isolated from the urine of patients with multiple myeloma. Four lines of evidence identify cubilin, a giant glycoprotein receptor, which is restricted in distribution to endocytic scavenger pathways and which has potent effects on endosomal trafficking, as a potentially physiologically relevant binding site for light chains: 1) light chains coeluted during immunoaffinity purification of cubilin; 2) polyclonal antisera to cubilin but not control sera, displaced human light chain binding from rat renal brush-border membranes; 3) cubilin bound to multiple species of light chains during surface plasmon resonance; 4) anti-cubilin antiserum interfered with light chain endocytosis by visceral yolk sac epithelial cells. However, both binding of light chains to brush-border membranes and endocytosis of light chains by yolk sac epithelial cells were only partially inhibited by anticubilin antibodies, suggesting presence of additional or alternate binding sites for light chains. Excess light chain had a potent inhibitory effect on endosomal fusion in vitro. Binding showed dose and time-dependent saturability with low-affinity, high-capacity equilibrium binding parameters. These data demonstrate that cubilin plays a role in the endocytosis and trafficking of light chains in renal proximal tubule cells.

Differential stimulation of c-fos expression in hypothalamic nuclei of the rat brain during short-term heat acclimation and mild dehydration

Activation of central nervous structures involved in the perception and integration of thermo- and osmoregulatory signals was investigated in the Sabra rat. Male rats were either non-treated (C-E), water-deprived for 24 h (C-D), short-term acclimated to 34 degrees C for two days (STHA-E) or subjected to both stimuli (STHA-D). Immunoreactivity for c-Fos protein (Fos-IR) as marker for neuronal activation was quantified in (extra-)hypothalamic structures: organum vasculosum laminae terminalis (OVLT); subfornical organ (SFO); medial (MPA), ventromedial preoptic (VMPO) and lateral hypothalamic (LHA) areas; median preoptic (MnPO), magnocellular supraoptic (SON) and paraventricular (mPVN) nuclei; limbic lateral septal (LS) and thalamic paraventricular (PV) nuclei. Compared to C-E rats, dehydration markedly increased Fos-IR exclusively in neurons of the OVLT, SFO and MnPO known to be involved in osmoreception, in the mPVN and SON, and to a minor extent in the VMPO. The VMPO, MPA, LHA and LS-important (extra-)hypothalamic sites for the perception and integration within the thermoregulatory control circuit-exhibited intense elevation of Fos-IR upon short-term heat acclimation. Of all (extra-)hypothalamic structures involved in central osmoregulation, only the MnPO revealed heat-induced Fos-IR in numerous cells located preferentially in its rostral component. Thus, the MnPO proved to be activated during both thermal and osmotic stimulations applied separately. Subjected to the combined stress (STHA-D), most brain structures investigated showed striking Fos-IR due to thermally enhanced osmotic stimulation, with additive effects demonstrated in the MnPO. The data support differential central activation of c-fos expression due to thermal or osmotic stimulations, with the MnPO acting as putative integrative center for both autonomic control circuits.

Dose response and concentration response relationship of apomorphine in patients with Parkinson's disease and end-of-dose akinesia

The motor response and the PK-PD relationship of the dopamine agonist, apomorphine, after ascending single doses (0.5, 1, 2, 4 mg s.c.), was investigated in 10 patients with advanced Parkinson's disease presenting end-of-dose motor fluctuations. Aim of the study was to investigate the exact pharmacodynamic effects of different apomorphine doses on the magnitude and duration of motor responses in parkinsonian fluctuators. The average improvement in the magnitude of the motor response (% change of baseline score in the Columbia University Rating Scale) elicited by apomorphine was negligible with 0.5 mg, 10% after the 1 mg dose, 22% after 2 mg, and 25% after 4 mg. If a 20% improvement is considered clinically relevant, a response was seen in 0/10 patients (0.5 mg), 2/10 patients (1 mg), 6/10 patients (2 mg), and 6/8 patients (4 mg). The duration of response was about 0.25 h (1 mg), 0.58 h (2 mg), and 0.72 h (4 mg). An explorative analysis of individual plasma concentration vs. effect curve, yielded a steep, sigmoidal concentration effect relationship with fast equilibrium at the effect site. The EC50 of the individual curves averaged 20 pMol/ml. However, several curves exhibited proteresis, making the application of a PK-PD model impossible. The reason for proteresis is not clear, it might indicate acute tolerance as well as a redistribution of apomorphine from the effect site.

Spinal neuronal thermosensitivity in vivo and in vitro in relation to hypothalamic neuronal thermosensitivity

In the spinal cord, temperature signals are generated which serve as specific inputs in the central nervous control of body temperature. Because of the spatially distinct organization of afferent and efferent neuronal systems at the spinal level, the afferent pathway for temperature signal transmission could be identified in vivo in the ascending, anterior and lateral tracts with a relationship of about 75:25% between warm and cold sensitive neuraxons. Analysis of spinal neuronal thermosensitivity in vitro on spinal cord tissue slices has been concerned, so far, with the superficial laminae of the dorsal horn as the site of origin of ascending nerve fibers conveying mostly temperature and pain signals, and with lamina X as a site of origin of afferent as well as efferent neurons. A relationship of about 95:5% between warm and cold sensitive neurons was found at the segmental level, indicating that warm sensitivity is the prevailing, primary property of spinal neurons, whereas cold sensitivity seems to be mainly generated by synaptic interaction as a secondary modality. Dynamic responses to temperature changes were frequently displayed in vitro at the spinal segmental level in lamina I + II but not in lamina X, even by neurons whose static activity was little influenced by local temperature. Dynamic thermosensitivity was found less frequently in ascending tract neuraxons and was not observed in hypothalamic neurons receiving temperature signal inputs from the spinal cord, and thus, does not seem to be relevant for the thermosensory function of spinal cord neurons, unlike peripheral warm and cold receptors. A majority of spinal warm sensitive neurons displayed both static and dynamic warm sensitivity as an inherent property after synaptic blockade. In the further analysis of spinal cord thermosensitivity, the in vitro approach permits application of the same electrophysiological and neuropharmacological methods as were established for the analysis of hypothalamic thermosensitivity. In addition, the topography of the spinal cord will provide additional structural and possibly histochemical information to characterize the functions of neurons independently of their thermal properties.

[Vasculitis affecting the kidney: analysis of 18 patients]

OBJECTIVE

Eighteen patients who were judged to have systemic vasculitis (1990 American College of Reumathology criteria) affecting the kidney, from January 1988 to August 1996, were reviewed.

METHOD

We analyzed characteristics of clinical, biochemical, histopathological features, the interval between the onset of the symptoms to a diagnosis of disease, treatment and overall outcome.

RESULTS

The principal mode of presentation of the vasculitis is general, renal and pulmonary symptoms. The discovery of ANCA has improved the diagnostic procedure in patients with these diseases. Renal biopsy facilitates early diagnosis, prognosis and treatment. The renal lesion typically shows a segmental necrotizing glomerulonephritis and extracapillary proliferation forming crescent.

CONCLUSIONS

The systemic vasculitis with renal involvement carries a poor prognosis and high mortality. A variety of treatment has been employed, but their precise role in the management of these vasculitis is still being elucidated.

Erythrocyte antioxidant status in asymptomatic hypercholesterolemic men

An imbalance between antioxidant and oxidant-generating systems leading to an oxidative stress has already been proposed in the pathogenesis of atherosclerosis. In the present study we investigated the antioxidant status in 60 asymptomatic hypercholesterolemic (HC) men compared with 48 normocholesterolemic (NC) men. Hypercholesterolemic subjects had a significantly lower red blood cell vitamin E (vit E-RBC) content in spite of their normal total plasma and HDL vitamin E concentrations. Activities of erythrocyte superoxide dismutase and glutathione peroxidase were not significantly different between groups. We also determined the resistance of RBCs to an oxidative stress by determining the extent of hemolysis induced by a water-soluble azo-compound. This resistance was significantly decreased in HC men compared with NC subjects. These results demonstrate an altered antioxidant status of RBC in asymptomatic HC men associated with an increased erythrocyte susceptibility to an oxidative stress. The measure of the vitamin E content in RBC might be the most sensitive parameter for evidencing early oxidative stress which does not need an adaptation of enzymatic protective systems.

[Medical treatment exclusively for cervical pregnancy with in situ methotrexate]

We present a case report of cervical pregnancy with medical treatment. Medical treatment consisted in injection of methotrexate (50 mg) into the pregnancy, on the first, third and seventh day. Ultrasound and Doppler give important information for follow up. The pregnancy totally resolved and the patient did not need any further treatment.

Transabdominal preperitoneal herniorraphy: technique and results

As enthusiasm for laparoscopic surgery has grown, laparoscopic approaches to the groin hernia have evolved. The most widely accepted laparoscopic repair employs the placement of a large sheet of mesh in a preperitoneal position to cover potential hernia spaces. Between March 1994 and February 1997 160 inguinal and 3 femoral hernia were operated of an transabdominal preperitoneal (TAPP) polipropylen mesh. 131 patients were operated (128 males and 3 females, ranging in age from 19 to 82 years), 31 (23%) of them had bilateral hernias. Recurrent hernia was the indication in 52 (32%) cases. Average operating time for unilateral repair was 80 minutes and for bilateral repairs was 108 minutes. Postoperative complications included 7 (4.3%) cases of transient neuralgias, 20 (12%) cord/scrotal transient seromas-hematomas and 2 (1.2%) hydrocele. The 5 (3.1%) early recurrences were considered to be caused by technical inexperience and/or too small prosthetic patch. The laparoscopic hernioplasty has definitive advantage: minimal postoperative pain, short hospital stay (average postoperative time of hospitalization 3.1 days) and early restoration of full physical activity (in 1 to 2 weeks). The method should be considered as a potential "best option" in patients with recurrences and bilateral inguinofemoral hernias.

Heterogeneous actions of vasopressin on ANG II-sensitive neurons in the subfornical organ of rats

The aim of this study was to investigate the effects of the antidiuretic hormone arginine vasopressin (AVP), which is released in vivo during dehydration and hypovolemia to prevent further water loss, on the activity of neurons in the subfornical organ (SFO). The SFO is a brain structure with an open blood-brain barrier and is critically involved in angiotensin II (ANG II)-dependent water intake. SFO neurons were recorded extracellularly in tissue slices of the rat brain and were tested for responsiveness to AVP and ANG II. About one-half of 159 neurons tested with an AVP concentration of 10(-6) M in the superfusion medium were responsive, and approximately equal proportions were excited and inhibited. Neurons exhibiting the different response types did not differ from each other with respect to spontaneous discharge rate, latency, and duration of the response. Excitatory and inhibitory responses to AVP were dose dependent and reversible, and their threshold concentrations (10(-8) to 10(-9) M) were similar. Superfusion with a medium low in Ca2+ and high in Mg2+ showed that the excitatory effect is most likely direct, whereas the inhibitory effect largely depends on inhibitory synaptic interaction. About one-half of the SFO neurons excited by ANG II (10(-7) M) were responsive to AVP (10(-6) M), and equal proportions were inhibited and excited. Both excitatory and inhibitory AVP actions were blocked by the V1-receptor antagonist, Manning compound, and neurons responsive to AVP did not respond to the V2-receptor agonist [deamino-Cys1,D-Arg8]vasopressin. It is concluded that AVP, probably released from synaptic terminals, may increase or decrease the activity of neurons in the SFO, many of which are activated by ANG II. In contrast to previous experiments on ducks, in which the exclusively excitatory effect of the avian antidiuretic hormone arginine vasotocin on ANG II-sensitive SFO neurons correlates well with the dipsogenic effect of both peptides, a greater functional heterogeneity exists among AVP-responsive neurons in the rat SFO.

Association between carriage of oral yeasts, malnutrition and HIV-1 infection among Tanzanian children aged 18 months to 5 years

The objective was to determine whether there is an association between carriage of oral yeasts, malnutrition and HIV-1 infection among Tanzanian children. A case-control study design within a cross-sectional study was used, and the outcome was carriage of oral yeasts. The exposure variables were malnutrition and HIV-1 antibody, and confounders to be adjusted for were age, sex, and breastfeeding. The study was carried out in Dar-es-Salaam, Tanzania, in two maternal and child health (MCH) clinics that offer routine medical checkups to all expectant mothers and children aged between 0 and 5 years in the catchment area. A total of 882 children aged between 18 months and 5 years participated. Smears from the tongue and buccal mucosa were examined for oral yeasts. Malnutrition was categorized according to standards on the MCH chart and World Health Organization/Centers for Disease Control (WHO/CDC) standards as weight-for-height (wasted), weight-for-age (underweight), and height-for-age (stunted). HIV-1 infection was determined by an enzyme-linked immunosorbent assay. Reactive sera were confirmed by Western Blot. About 27% of the children were slightly or severely malnourished according to standards on the MCH chart. According to WHO/CDC standards, 2.6% were wasted, 16.3% were underweight, and 29.6% were stunted. Fourteen (1.6%) were seropositive for HIV-1 antibody. Hyphal forms and blastospores were much more frequent among children infected with HIV-1 with odds ratios ranging from 3.8 (95% CI: 1.3;11.2) to 6.2 (95% CI: 2.1;18.4) depending on categorization of malnutrition. Malnutrition was a risk factor, too, albeit to a much lesser and insignificant degree. The study supports our previous findings that malnutrition may predispose to carriage of oral yeasts and subsequent infection. However, in this study population HIV infection was clearly the predominant risk factor.

Nutritional status of under fives attending maternal and child health clinics in Dar es Salaam, Tanzania

We designed a study to assess the nutritional status of children under five years of age attending MCH clinics in Dar es Salaam. This was a cross-sectional anthropometric study involving children 6-24 months who from July to August 1993 were attending Magomeni MCH clinic and those aged 18 months to five years who were attending Lugalo and Mwananyamala MCH clinics for routine growth monitoring and for vaccination between May to August 1994. The data collected included age, birthweight, sex, weight, height, breastfeeding status and HIV-1 serostatus. Of the 1854 children enrolled (961 boys and 893 girls) 31.6% were stunted, 14.6% were underweight and 2.9% were wasted. The highest percentage of stunting and wasting was observed between 11 and 25 months and 36 to 40 months. Of the 849 children tested for HIV-1, 14 (1.7%) were seropositive and two out of 770 (0.3%) were born with low weight. HIV seropositivity and low birthweight were both associated with stunting and wasting. We conclude that malnutrition is still a sizeable problem among children attending urban MCH clinics in Dar es Salaam especially among those aged less than three years, to whom special malnutrition control strategies should be targeted. There is also a need to identify factors responsible for the observed decline in MCH attendance with age and correct the situation.