Pancreatic islet beta cell protective effect of oral vanadyl sulphate in streptozotocin-induced diabetic rats, an ultrastructure study

We sought to determine the ultrastructure of pancreatic islet beta cells of streptozotocin-induced diabetic rats treated with oral vanadyl sulphate. Diabetes was induced in male Wistar rats by intravenous injection of 40 mg kg(-1) streptozotocin. The same volume of normal saline was injected in sham animals. Animals were divided into treated and control groups. Vanadyl sulphate was added to the drinking water of the treated animals at a concentration of 1 mg mL(-1) up to three months. Two months after vanadyl sulphate withdrawal animals were killed. Ultrastructure of islet beta cells were studied by transmission electron microscope. In diabetic treated rats plasma glucose and fluid intake returned to normal levels within three months while control animals remained diabetic. Well granulated cytoplasm, well developed endoplasmic reticulum, increase in the number of immature granules in the cytoplasm with no clear signs of cell injury were found in the islet beta cells of diabetic treated rats. Lymphocyte filteration, nuclear picnosis, cytoplasmic vacuolization were found frequently in the islet beta cells of untreated diabetic rats. In conclusion as was evident in thin sections of panceatic islet beta cells of treated diabetic rats in this study, vanadyl sulphate through preserving islet beta cells structure and ultrastructure contributes in reversing diabetic signs and symptoms in streptozotocin induced diabetic rats.

N-methyl-D-aspartate receptors are involved in lithium-induced state-dependent learning in mice

We have previously shown lithium-induced state-dependent learning in a step-down inhibitory avoidance task. In the present study, the effects of intracerebroventricular injections of N-methyl-D-aspartate (NMDA) receptor agents on the lithium-induced state-dependent learning have been investigated. A single-trial step-down inhibitory avoidance task was used to assess memory in male Naval Medical Research Institute (NMRI) mice. The results showed that post-training lithium (10 mg/kg) decreased the step-down latency on the test day, which was reversed by pre-test administration of the same dose of the drug; indicating state-dependent learning induced by lithium. Pre-test administration of NMDA (0.0001, 0.001 and 0.01 microg/mouse, intracerebroventricular) could also substitute for pre-test lithium to reverse the decrease of the step-down latency induced by post-training lithium. Furthermore, pre-test co-administration of an ineffective dose of NMDA (0.00001 microg/mouse, intracerebroventricular.) with lower doses of lithium (1.25, 2.5 and 5 mg/kg, intraperitoneally.) synergistically reversed the decrease of the step-down latency. On the contrary, pre-test injections of NMDA receptor antagonist D-AP5 (0.25, 0.5, 1 and 2 microg/mouse, intracerebroventricular.) disrupted state-dependent learning induced by lithium. The results suggest that NMDA receptors may be involved, at least partly, in the lithium-induced state-dependent learning.

Repeated administrations of dopamine receptor agents affect lithium-induced state-dependent learning in mice

The influence of repeated administration of dopamine receptor agents on the effect of lithium on lithium-induced state-dependent learning was examined in mice. Immediate post-training intraperitoneal (i.p.) administrations of lithium (10 and 20 m/kg) decreased the step-down latency of a single-trial inhibitory avoidance task. This was fully or partly reversed by pre-test administration of the same doses of the drug, with maximum response at the dose of 10 mg/kg, suggesting state-dependent learning was induced by lithium. Here, it has also been shown that repeated intracerebroventricular administrations of a mixed D1/D2 dopamine receptors agonist apomorphine (once daily injections of 0.5 microg/mouse for three consecutive days followed by five days of no drug treatment) increased the effect of lower doses of pre-test lithium (1.25, 2.5 and 5 mg/kg, i.p.) on the reinstatement of the step-down latency decreased by post-training lithium (10 mg/kg). On the contrary, not only repeated administrations of the dopamine D1 receptor antagonist SCH 23390 (0.5 and 1 microg/mouse) but also the dopamine D2 receptor antagonist sulpiride (0.3 and 1 microg/mouse) disrupted the state-dependent learning induced by lithium. These results suggest that state-dependent learning induced by lithium may be altered by repeated pretreatment of dopamine receptor agents.

N-methyl-D-aspartate Receptors are Involved in the Effect of Lithium on Passive Avoidance Memory in Mice

In the present study, the effects of intracerebroventricular (i.c.v.) injections of N-methyl-D-aspartate (NMDA) receptor agonist and antagonist on the lithium state-dependent memory have been investigated. For memory assessment, one-trial step-down passive avoidance task was used in adult male NMRI mice. Post-training intraperitoneal (i.p.) administration of lithium (10 mg/kg) impaired the memory of passive avoidance task. Pre-test administration of the same dose of the drug (10 mg/kg) restored impairment of memory by lithium given after training. This is known as state-dependent memory. In addition, pre-test administration of both NMDA receptor agonist (NMDA; 0.01 and 0.1 ng/mouse, i.c.v.) and the non-competitive NMDA receptor antagonist, MK-801 (0.1 and 0.5 mg/mouse, i.c.v) also restored impairment of memory induced by post-training lithium. On the other hand, pre-test co-administration of ineffective dose of NMDA (0.001 ng/mouse, i.c.v.) or MK-801 (0.001 mg/mouse, i.c.v) with lower doses of lithium (1.25, 2.5 and 5 mg/kg, i.p.) increased the restoration of memory by lithium. The results suggest that NMDA receptors are involved, at least partly, in the lithium state-dependent memory of passive avoidance task.

[Uterine rupture of the unscarred uterus. About 28 cases]

OBJECTIVES

To determine the etiologic factors explaining the appearance of uterine rupture on unscarred gravid uterus and to value the maternal and foetal prognosis of this complication.

PATIENTS AND METHODS

The authors report a study of 28 cases of uterine rupture on unscarred gravid uterus, recorded between January 1989 and December 1997, at the department of obstetrics and gynecology, Farhat Hached University Hospital, Sousse, Tunisia.

RESULTS

Out of the 72283 deliveries during the study period, there were 28 ruptured uteri of unscarred uterus giving a hospital incidence of one in 2581 deliveries. Multiparity, neglected labour dystocia and obstetric procedure were the common etiologic factors accused in the occurring of this complication. To be added to these factors: the low socio-economic status of the patients and lack of antenatal care. The surgical management was conservative (repair) in 19 cases (67.9%); hysterectomy was indicated in nine cases (32.1%). Maternal and fetal morbidity and mortality were important: we deplore two maternal deaths (7.1%) and seven fetal deaths (24.1%).

DISCUSSION AND CONCLUSION

Uterine rupture on unscarred uterus is a relatively rare complication of the pregnancy. However, its incidence remains high in developing countries. Its occurrence is significantly associated with grandmultiparity, lack of antenatal care and low socio-economic status of the patients.

Keratitis-ichthyosis-deafness syndrome and carotenaemia

Keratitis-ichthyosis-deafness (KID) syndrome is a congenital ectodermal disorder that causes erythrokeratoderma, vascularizing keratitis, and neurosensory deafness. We report a form of this syndrome in a patient with no evidence of keratitis. In addition this individual had clinical and biochemical evidence of carotenaemia. Carotenaemia occurring in association with KID syndrome has not been reported previously.

Modulation of synaptic transmission by nociceptin/orphanin FQ and nocistatin in the spinal cord dorsal horn of mutant mice lacking the nociceptin/orphanin FQ receptor

Nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) are two neuropeptides derived from the same precursor protein that exhibit opposing effects on spinal neurotransmission and nociception. Here, we have used whole-cell, patch-clamp recordings from visually identified neurons in spinal cord dorsal horn slices of genetically modified mice to investigate the role of the N/OFQ receptor (N/OFQ-R) in the modulatory action of both peptides on excitatory glutamatergic and inhibitory glycinergic and gamma-aminobutyric acid (GABA)-ergic synaptic transmission. In wild-type mice, N/OFQ selectively suppressed excitatory transmission in a concentration-dependent manner but left inhibitory synaptic transmission unaffected. In contrast, NST reduced only inhibitory but not alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated excitatory synaptic transmission. N/OFQ-mediated inhibition of excitatory transmission was completely absent in N/OFQ-R receptor-deficient (N/OFQ-R(-/-)) mice and significantly reduced in heterozygous (N/OFQ-R(+/-)) mice, whereas the action of NST on inhibitory neurotransmission was completely retained. To test for the relevance of these results for spinal nociception, we investigated the effects of intrathecally injected N/OFQ in the mouse formalin test, an animal model of tonic pain. N/OFQ (3 nmol/mouse) induced significant antinociception in wild-type mice, but had no antinociceptive effects in N/OFQ-R(-/-) mice. These results indicate that the inhibitory action of N/OFQ on excitatory glutamatergic synaptic transmission and its spinal antinociceptive action are mediated via the N/OFQ receptor, whereas the action of NST is independent of this receptor.

The role of the ORL1 receptor in the modulation of spinal neurotransmission by nociceptin/orphanin FQ and nocistatin

Nociceptin/orphanin FQ and nocistatin are two neuropeptides with opposing effects on spinal neurotransmission and nociception. Nociceptin/orphanin FQ selectively suppresses excitatory glutamatergic neurotransmission, while nocistatin selectively interferes with glycinergic and gamma-aminobutyric acid (GABA)-ergic transmission. Here, we performed whole-cell patch-clamp recordings from superficial rat spinal cord dorsal horn neurons to investigate the role of the opioid receptor-like (ORL)1 receptor for modulatory actions of these peptides. The partial ORL1 receptor antagonist [phe1psi(CH(2)-NH)Gly(2)]nociceptin-(1-13)NH(2) competitively reversed the effects of nociceptin/orphanin FQ on excitatory neurotransmission (estimated pA(2) 6.43), but left the suppression of inhibitory synaptic transmission by nocistatin unaffected. These results indicate that the inhibitory action of nociceptin/orphanin FQ on glutamatergic transmission is mediated via ORL1 receptors, while nocistatin acts via a different so far unidentified receptor.

Reconciling quantitative ultrasound of the calcaneus with X-ray-based measurements of the central skeleton

Osteoporosis is frequently undiagnosed before fracture because of the lack of availability of instruments to quantitate bone mass. To evaluate the utility of quantitative ultrasound (QUS) of the calcaneus to diagnose osteoporosis, we determined bone mineral density (BMD) of the posterior-arterior spine, total hip, and femoral neck by dual-energy X-ray absorptiometry (DXA) and QUS in 312 women aged 50 years and older. A risk factor assessment (simple calculated osteoporosis risk estimation [SCORE]) also was quantitated in all women. Ninety-four of the 312 women were diagnosed as osteoporotic based on T scores < or = -2.5 at the spine, total hip, and/or femoral neck. The sensitivity of the individual central sites for the diagnosis of osteoporosis was 49% at the spine (46 of 94 women), 32% at the total hip (30 of 94 women), and 81% at the femoral neck (76 of 94 women). At a QUS T score < or = -1, the peripheral technique had a sensitivity of 62% and a specificity of 72%. Combining a QUS T score of < or = -1 followed by a risk factor assessment of women with a QUS T score > or = -0.99 using a cut point of 11 increased sensitivity to 81% (comparable with femoral neck DXA) but decreased specificity to 58%. If peripheral QUS measurements and risk factor assessment are the only tools employed before initiation of therapy, the benefits of increased ease of diagnosis will need to be balanced against potentially unnecessary treatment in some normal patients and lack of treatment in some osteoporotic patients.

Selective suppression of inhibitory synaptic transmission by nocistatin in the rat spinal cord dorsal horn

Nociceptin/orphanin FQ (N/OFQ) and nocistatin (NST) are two recently identified neuropeptides with opposing effects on several CNS functions, including spinal nociception. The cellular mechanisms that underlie this antagonism are not known. Here, we have investigated the effects of both peptides on synaptic transmission mediated by the three fast neurotransmitters l-glutamate, glycine, and GABA in the superficial layers of the rat spinal cord horn, which constitute the first important site of integration of nociceptive information in the pain pathway. NST selectively reduced transmitter release from inhibitory interneurons via a presynaptic Bordetella pertussis toxin-sensitive mechanism but left excitatory glutamatergic transmission unaffected. In contrast, N/OFQ only inhibited excitatory transmission. In the rat formalin test, an animal model of tonic pain in which N/OFQ exerts antinociceptive activity, NST induced profound hyperalgesia after intrathecal application. Similar to glycine and GABA(A) receptor antagonists, NST had no significant effects in the rat tail-flick test, a model of acute thermal pain. Our results provide a cellular basis for the antagonism of N/OFQ and NST and suggest the existence of a so far unidentified membrane receptor for NST. In addition, they support a role of NST as an endogenous inhibitor of glycinergic and GABAergic neurotransmission in the sensory part of the spinal cord and as a mediator of spinal hyperalgesia.

Quantitative ultrasound: an indicator of osteoporosis in perimenopausal women

The key to effective treatment of osteoporosis is early detection; however, the disease in perimenopausal women is frequently undiagnosed. To assess the utility of quantitative ultrasound (QUS) at the calcaneus in perimenopausal women, broadband ultrasound attenuation (BUA); speed of sound (SOS); quantitative ultra-sound index (QUI), an algorithm of BUA and SOS; and bone mineral density by dual X-ray absorptiometry (DXA) of the posteroanteiror spine, femoral neck, and total hip were measured in 420 women (ages 45-55 yr). Thirty (7.1%) of the women were found to be osteoporotic by DXA. All QUS measurements were predictors of osteoporosis. QUS values did not differ between postmenopausal women on estrogen replacement therapy (ERT) and those not on ERT. There were no differences among BUA, SOS, and QUI in the area under the receiver operating characteristic curves for predicting osteoporotic vs nonosteoporotic cases. At a QUI of 89, ultrasound had an 80% sensitivity for the diagnosis of osteoporosis, but only a 74% specificity. The use of QUS in perimenopausal women will facilitate the identification of women with osteoporosis. However, the high false-positive rate (26%) limits the utility of QUS as the sole diagnostic technique on which to base therapeutic decisions. Nevertheless, low QUS measurements may provide a means for targeting those women who would benefit most from more extensive evaluation (e. g., DXA).

Bone mineral density and broadband ultrasound attenuation with estrogen treatment of postmenopausal women

The purpose of the current study was to determine the changes in lumbar spine, hip, and calcaneus bone mineral density (BMD), and in calcaneus broadband ultrasound attenuation (BUA) in early menopausal women and to assess the effects of estrogen replacement therapy (ERT) on bone mass at these sites over a 2-yr period. Fifty-three Caucasian women who were at least 6 mo postmenopausal were divided into two groups based on estrogen use. Twenty-one women, average age 53.0 +/- 0.6 yr and 2.9 +/- 0.3 yr since menopause, had been receiving estrogen in combination with progesterone for at least 6 mo prior to enrollment in the study. Thirty-two women, average age 52.7 +/- 0.8 yr and 2.8 +/- 0.3 yr since menopause, had never received ERT. During the 2-yr study, women not receiving ERT had significant decreases in BMD of the spine -2.3 +/- 0.6%, femoral neck -2.2 +/- 0.8%, and calcaneus -4.7 +/- 0.9%, and in BUA of the calcaneus -14.3 +/- 1.8%. ERT prevented the decreases in BMD at the spine +0.4 +/- 0.6% and calcaneus -2.3 +/- 1.1%, but did not prevent a significant decrease in bone mass at the femoral neck -1.9 +/- 0.8% and BUA at the calcaneus -17.8 +/- 3.2%. Neither group had significant decreases in total hip BMD. This study demonstrates again that ERT prevents the menopause-associated decreases in spine BMD. However, in this group of women, ERT did not prevent loss in femoral neck BMD or BUA. The results suggest that women being treated with estrogen for maintenance of BMD in early menopause need to be monitored to ensure efficacy of therapy, especially in the maintenance of femoral neck BMD.

Effects of vanadyl sulphate on glucose homeostasis in severe diabetes induced by streptozotocin in rats

Rats made severely diabetic by an i.v. injection of 50-55 mg/kg streptozotocin (STZ), 15 days later showed blood glucose > 500 mg/dl, quadrupled daily water intake and plasma insulin of 14 +/- 3 microU/ml, about 25 per cent that of normal rats. Subsequently, these rats in two groups, received 0.5-1 mg/ml vanadyl sulphate in base solution (vanadyl) orally (Group I) and base solution containing 50 mEq/1 NaCl (Group II). Since 90 days of vanadyl therapy could not decrease blood glucose of group I (420 +/- 10 mg/dl) to normal levels, euglycaemia was achieved for a period of two months by intraperitoneal (i.p.) injection of NPH insulin. The required daily doses of insulin in vanadyl-treated rats of group I (8 +/- 1 U/kg/day) were only 8 per cent of those in group II animals (103 +/- 7 U/kg/day). In conclusion, it seems that vanadyl per se cannot induce normoglycaemia in diabetic rats with very low plasma insulin levels, but can augment the sensitivity of peripheral tissues to insulin.

Effect of bovine bone constituents on broadband ultrasound attenuation measurements

Broadband ultrasound attenuation (BUA) has been found to correlate positively with bone mineral density (BMD) measured by dual-energy X-ray absorptiometry. However, because there is a significant amount of unexplained variation in this correlation, it has been suggested that BUA might also provide information about bone structure. The purpose of this study was to determine the contribution of bone mineral and organic matrix to BUA and BMD measurements. The influence of sample length on both BUA and BMD was also investigated by normalizing these measurements to length. BUA (Walker Souix, 575+) and BMD (Lunar DPX) values were obtained on bicortical cores removed from 12 bovine femoral necks. BMD and BUA measurements were repeated on the samples after: (1) mechanical removal of the cortices; (2) defatting using a 2:1 chloroform:methanol solution; and (3) decalcifying using formic acid. The data demonstrate that the cortical component of the bone contributes significantly to BMD. We found that 41.7% of the normalized BMD reflect cortical bone. Defatting the samples did not affect BUA. Decalcifying the trabecular bone while maintaining an intact collagenous structure significantly reduces BUA by 89% and BMD by 96% compared to the whole core samples. Normalizing BMD and BUA to sample length, in cases where large variation is present, does influence the correlation between the variables. We conclude that BUA is influenced mainly by the presence of bone mineral, whereas the presence of the organic matrix contributes very little to BUA.

Correlations among bone mineral density, broadband ultrasound attenuation, mechanical indentation testing, and bone orientation in bovine femoral neck samples

Broadband ultrasound attenuation (BUA) of the calcaneus has been found to correlate with bone mineral density (BMD) of the femoral neck. The purpose of this study was to determine if a correlation exists among femoral neck BUA, femoral neck BMD, and incremental indent depth, a qualitative indicator of local mechanical bone strength, in bovine samples, and if this correlation is dependent upon orientation. For 12 of the bovine samples obtained, BUA was measured at the femoral neck and was followed by a BMD determination of the same area. A 19 mm diameter bicortical core containing the center of the area of interest was removed, transversely cut into 7 mm, thick disks, and tested for hardness by indent depth. For these tests, BMD was well correlated with BUA (R2 = 0.85, P < 0.001). An inversely proportional relationship with a modest correlation was found between indent depth and BMD (R2 = 0.59, P = 0.026), and indent depth and BUA (R2 = 0.57, P = 0.031). In a second set of tests involving 15 different bovine samples, a bicortical core was removed from the femoral neck. A trabecular bone cube measuring 1.5 cm on a side was removed from the center of the core. BUA and BMD measurements were made along the anterior-posterior (AP), medial-lateral (ML), and cephalic-caudal (CC) aspects of the cube. The cubes were randomly separated into three groups, cut in half perpendicular to the axis of interest, and tested for hardness by indent depth. In these tests, no significant difference was found in BMD among the three orientations of the cubes scanned (P = 0.77). In contrast, the BUA along the ML orientation of the cube was significantly greater than that along the AP orientation (P < 0.05). No significant difference was found in the incremental indent depth measurements among cube orientations (P = 0.41). In the test involving only trabecular bone, a much higher correlation between BMD and incremental indent depth was found regardless of cube orientation (R2 = 0.64, P < 0.001). The data indicate that BUA, but not BMD, is affected by trabecular orientation, and that BMD is negatively correlated with incremental indent depth.

Model inconsistency, illustrated by the Cox proportional hazards model

We consider problems involving the comparison of two or more treatments where we have the opportunity to adjust for relevant covariates either conditionally in a regression model or implicitly in repeated measures data, for example, in crossover trials. It is seen that for data arising from non-Normal distributions there is the possibility that models adjusting for covariates and those not adjusting for covariates will be inconsistent, that is, at most one of the models can be valid. Alternatively, even if conditional and unconditional models are valid, parameters in each model may have different interpretations. We note that this presents difficulties for the specification and interpretation of the analysis. It is also clear that model validation is critical. Specific attention is paid to survival data analysed by the Cox proportional hazards model.