Suicide under the age of eighteen: a 10-year retrospective study

The number of suicides in the pediatric age group is rising, and death investigators need to be aware of the common scenarios, risk factors, and victims as they investigate such cases to properly assign the cause and manner of death. We reviewed all pediatric cases referred to the Medical University of South Carolina, Forensic Section, from January 1988 through January 1998. Thirty-one cases of pediatric suicide were analyzed with regards to age, gender, race, cause of death, surrounding circumstances, and past history. Sixty-eight percent of victims were aged 16 or 17 years, 84% were male, 68% were white, 78% used firearms to commit suicide, 81% were found within close vicinity of their home, and 26% had a documented history of mental illness. Suicide is a manner of death that is often difficult for the public to accept, especially in pediatric cases. We report our findings in this 10-year retrospective study to better understand this entity and work toward the prevention of future cases.

The removal of beta-2-microglobulin by an immunoadsorption wall

The accumulation of beta-2-microglobulin (beta2M) in collagen-rich tissues has been proven to be the main cause of dialysis related amyloidosis. However, it remains uncertain which technique for the removal of beta2M can be used without compromising the advantages of other dialysis strategies. A new concept, an immunoadsorption wall, which combines the principles of immunoisolation and immunoadsorption is proposed to remove beta2M. The present investigations suggested that the application of the concept to clinical use is feasible and worthwhile. The concept, if validated, will help shape a novel multitask type of artificial kidney based on the combination of different separation technologies.

The merit of sintered PDLLA/TCP composites in management of bone fracture internal fixation

Polyesters based on lactic acid have been reported in terms of safety and biodegradation in human beings for 2 decades. The greatest advantage of such material is its degradation conducted only by hydrolysis, whereby the ester backbones are supposed to be unchained in the aqueous condition. The final degradable products are carbon dioxide and water which can be metabolized and digested in the physiological environment. The goal of this study was aimed at developing a composite sintered with poly-DL-lactide (PDLLA) and tricalcium phosphate (TCP) ceramic particles for orthopedic application. The TCP particles in a range of 30-60 wt% with 5 wt% increments were doped into the PDLLA matrix which was prepared by melting and hot pressing techniques for the reinforcement. The basic mechanical strength, biodegradable behavior, and biological response of the composites were investigated in the study. Various techniques such as pH meter, UV, Fourier-transform infrared, and x-ray diffractometer were used to examine and record the degradable process of the composites soaked in saline for 1-16 weeks. The rabbit femur condyle fracture fixation test was used to evaluate tissue compatibility and the effects of bone fracture fixation on the composites. Histological observation and x-ray photography were used for investigating assistance. The mechanical strength of the composites initially increased with TCP additions up to 50wt%, but thereafter they showed no significant difference (p < 0.05). The composite with 50 wt% TCP addition showed greater mechanical strength and had good agreement with cortical bone in terms of its elastic modulus of 30-40 GPa. The weight loss of the pure PDLLA soaked in the saline started at 4 weeks and reached 95% after 16 weeks. The composites compared with pure PDLLA, however, showed no apparent evidence of degradation after soaked for 12 weeks. The possible mechanisms for the delayed degradation of the composites in saline might have been solution penetration retardation by the ceramic particles and chemical bonds formed between the interface of the TCP particles and the PDLLA matrix. In the histological evaluation of the rabbit femur condyle fracture fixation test, the surface of the composite with 50 wt% TCP addition was attached by the newly generated bone without fibrous tissue around 8 weeks after implantation. The fractured bone was gradually healed and the composite firmly and properly fixed on the fracture area during the implanted period, which provided a breeding environment for normal bone remodeling. The developed composite was thought to be an alternative material for orthopedic application in the future, especially for bone screws and bone plates.

Effect of alterations in extracellular norepinephrine on adrenoceptors: a microdialysis study in freely moving rats

Chronic electroshock treatment (once daily for 12 days) increases extracellular norepinephrine in the frontal cortex and hippocampus as measured by microdialysis. This chronic treatment produced an elevation of basal norepinephrine overflow into extracellular space while both the first and the twelfth treatments produced a transient increase in norepinephrine overflow of about 40 min. Acutely, desmethylimipramine (10 mg/kg) treatment significantly increased extracellular norepinephrine. While chronic desmethylimipramine (once daily for 10 days) increased basal overflow of norepinephrine in the frontal cortex and hippocampus, the tenth daily administration of desmethylimipramine did not produce a statistically significant increase in extracellular norepinephrine. Both daily electroshock and daily desmethylimipramine produced down regulation of beta-adrenoceptors in the hippocampus and the frontal cortex. Chronic electroshock caused up regulation of alpha-adrenoceptors in the frontal cortex but not in the hippocampus while chronic desmethylimipramine administration did not alter alpha-adrenoceptors in either structure. Depletion of norepinephrine with reserpine or with 6-hydroxydopamine prevented the down regulation of beta-adrenoceptors while depletion of this neurotransmitter did not prevent the electroshock-induced up regulation of alpha-adrenoceptors in the frontal cortex. These data suggest that down regulation of beta-adrenoceptors is mediated through increases in extracellular norepinephrine. In contrast, up regulation of alpha-adrenoceptors appears to be independent of norepinephrine release and does not require the presence of noradrenergic neurons in order to be induced by electroshock.

Gamma-radiation accelerates ovarian follicular atresia in immature mice

This study deals with the morphological degenerations of normal and atretic follicles based on artificially induced radiation apoptosis. ICR strain of 3 week-old female mice were whole body irradiated with 8.3 Gy and sacrificed by cervical dislocation. Ovaries were collected at 0 h, 6 h, 12 h, 1 d, 2 d, 4 d, and 8 d post irradiation and processed for morphological observation. Irradiated ovarian follicles showed such characteristics as faint connection between zona and cumulus thinning of granulosa layer, numerous apoptotic bodies, and increased cell debris in antrum. However, in normal ovaries about a half of the follicles were healthy. Within 6 h post irradiation, more than 95% of follicles steeply became apoptotic. At 4 d, severely damaged follicles with hypertrophed theca layer and fragmented oocytes were shown. At 8 d, normal shaped follicles were observed together with severely disrupted ones. The normal shaped follicles seemed to have grown from radioresistant ones. In conclusion, gamma-radiation had an additive or concomitant effect on atretic degeneration of mouse ovarian follicles.

Topographic localization of neuropeptide Y mRNA in the monkey brainstem

Neuropeptide Y (NPY) modulates cardiovascular, feeding and reproductive functions. Peripheral neurohumoral inputs from these systems are integrated and transformed into efferent signals in the brainstem. Detailed mapping of NPY-expressing cells in the brainstem has not been established in primates. In this report we utilized the in situ hybridization (ISH) method to identify brainstem areas that contain NPY mRNA in four ovariectomized rhesus macaques treated with estradiol-17beta. A 35S-labeled human NPY cRNA probe was used for ISH in paraformaldehyde-fixed brainstem blocks that were sectioned at 20 microm thickness. In the upper cervical spinal cord, NPY mRNA signals were confined to the substantia gelatinosa along the spinal tract of the trigeminal nerve. In the medulla, NPY images were found in the nucleus of solitary tract, dorsal motor nucleus of vagus nerve, nucleus of the spinal tract of trigeminal nerve, lateral reticular nucleus and the reticular formation. In the pons, NPY mRNA was confined to cells in the locus coeruleus and the nucleus of raphe. NPY signals were observed in the ventral portion of the periaqueductal grey, the dorsal nucleus of raphe and the reticular formation of mesencephalon in the midbrain. Whereas the brainstem distribution of NPY-containing cells in the rhesus macaque overlap those regions that are rich in catecholamines, NPY perikarya were also present in 'noncatecholaminergic' areas. For example, the reticular formation of both the medulla and mesencephalon abundantly expressed NPY mRNA. The functional significance of, and the effects of estrogen on, these patterns in NPY expression is unknown.

Enhanced hippocampal CA1 LTP but normal spatial learning in inositol 1,4,5-trisphosphate 3-kinase(A)-deficient mice

To define the physiological role of IP(3)3-kinase(A) in vivo, we have generated a mouse strain with a null mutation of the IP(3)3-kinase(A) locus by gene targeting. Homozygous mutant mice were fully viable, fertile, apparently normal, and did not show any morphological anomaly in brain sections. In the mutant brain, the IP4 level was significantly decreased whereas the IP3 level did not change, demonstrating a major role of IP(3)3-kinase(A) in the generation of IP4. Nevertheless, no significant difference was detected in the hippocampal neuronal cells of the wild-type and the mutant mice in the kinetics of Ca2+ regulation after glutamate stimulation. Electrophysiological analyses carried out in hippocampal slices showed that the mutation significantly enhanced the LTP in the hippocampal CA1 region, but had no effect on the LTP in dentate gyrus (DG). No difference was noted, however, between the mutant and the wild-type mice in the Morris water maze task. Our results indicate that IP(3)3-kinase(A) may play an important role in the regulation of LTP in hippocampal CA1 region through the generation of IP4, but the enhanced LTP in the hippocampal CA1 does not affect spatial learning and memory.

The preliminary study and tentative animal study on the sintered PDLLA/TCP composites as bone fracture internal fixation

Polyesters based on the lactic acid have been reported safety and biodegradation in the human beings for two decades. The greatest advantage of the material is its degradation only conducted by the hydrolysis, where the ester backbones are supposed to be unchained in the aqueous condition. The final degradable products are carbon dioxide and water which can be metabolized and digested in the physiological environment. The goal of this study was aimed to develop a composite sintered with poly-DL-lactide (PDLLA) and tricalcium phosphate (TCP) ceramic particles as orthopedic application. The TCP particles in a range of 30-60 wt% (with 5 wt% increment) were doped into the PDLLA matrix for the reinforcement, which were prepared by the melting and hot pressing techniques. The basic mechanical strength, biodegradable behavior, and biological response of the composites will be investigated in the study. Various techniques, such as pH meter, UV, FTIR, XRD ect., were used to examine and record the degradable process of the composites soaked in the saline for 1-16 weeks. The rabbit femur condyle fracture fixation test was used to evaluate the tissue compatibility and the effects of bone fracture fixation of the composites. The histological observation and x-ray photography were applied for investigating assistance. In the histological evaluation of rabbit femur condyle fracture fixation test, the surface of the composite with 50 wt% TCP addition was attached by the new generated bone without fibrous tissue around after 8 weeks implantation. The fracture bone was gradually healing and the composite always firmly and properly fixed on the fracture area during the implanted period, which provided a breeding environment for normal bone remodeling. The developed composite was thought to be an alternative material for orthopedic application in the future, especially in bone screw and bone plate.

The role of Müller's muscle reconsidered

It is a traditional teaching that the levator aponeurosis is the main transmitter of the levator palpebrae muscle. However, there are several points that raise doubts in this fundamental concept of the levator aponeurosis as being the primary interconnecting mechanism in upper lid elevation. Despite the structural integrity of the levator complex, drooping of the upper eyelids is seen to develop in situations such as Horner's syndrome and in times of excessive fatigue and sleepiness. Amid the controversy in the literature regarding the specific role of the levator aponeurosis in the lid-elevating mechanism, we have observed that the levator aponeurosis fails to make constant attachment to the tarsal plate. This has led us to speculate on the possible role of the posterior lamella - Müller's muscle - as the primary transmitter of the levator muscle action to the tarsal plate.

Possible involvement of norepinephrine transporter activity in the pulsatility of hypothalamic gonadotropin-releasing hormone release: influence of the gonad

Pulsatile secretion of hypothalamic gonadotropin-releasing hormone (GnRH) is suppressed by alpha-adrenergic antagonists in ovariectomized (OVX) rabbits, thus suggesting that initiation of GnRH pulses requires the presence of norepinephrine (NE) stimulation. Terminals of NE neurons are located in proximity with GnRH cells in the hypothalamus, including the arcuate nucleus-median eminence (AME) region. Synaptic NE molecules may be catabolized or transported back to NE terminals (i.e. reuptake) via specific NE transporter proteins (NET). Thus, the amount of synaptic NE acting on GnRH cells is a function of the rate of NE release, metabolism and reuptake. Hypothetically, the rise and fall of a GnRH pulse may be associated with the similar fluctuations of synaptic NE release and/or NET activity. To test this hypothesis, we examined the effects of AME administration of desipramine (DMI, a specific NET blocking drug) on GnRH release. First, we delivered 0.2-10 mM doses of DMI continuously for 1 h via an AME microdialysis (microD) system into intact male rabbits. We found that each AME-DMI infusion, between dosages of 1 mM and 10 mM, stimulated a GnRH pulse, and that the size of these GnRH pulses were proportional to the dosage of DMI. To confirm the specificity of DMI on NET, we measured catecholamine content in microD samples by HPLC. The temporal (60 min) DMI induced a pattern of NE release that included a rising limb within the first 20-30 min; although NE returned to baseline values within the period of DMI treatment. Neither epinephrine nor dopamine levels were changed by DMI. Second, a median dose of DMI (5 mM) was given by microD for 60 min in four separate rabbit models: gonadal intact females (F-INT), intact males (M-INT), gonadectomized females (F-GDX) and castrated males (M-GDX). Individual microD samples were measured for NE and GnRH. Regardless of gender or gonadal status, 5 mM of DMI concomitantly induced a pulse-like release of NE and GnRH. Furthermore, the response of GnRH to DMI was greater in GDX rabbits than in INT animals of both genders. Third, we administered DMI (5 mM) for 30 min via a push-pull perfusion (PPP) system during four repeated 90 min intervals, in either F-INT or ovariectomized (F-GDX) females, and measured GnRH in PPP samples. In both F-INT and F-GDX, each DMI challenge induced a GnRH pulse. In F-INT, all sequential DMI-induced GnRH pulses were nearly equal in size. In contrast, in F-GDX, the first DMI-induced GnRH pulse was greater than subsequent ones. Collectively, these observations are consistent with the concept of noradrenergic regulation of pulsatile GnRH release, and we conclude that the temporal activity of NET may be an integral part of the mechanism by which GnRH pulses operate.

Airway goblet cell mucin: its structure and regulation of secretion

Mucociliary clearance is a major function of the airway epithelium. This important function depends both on the physicochemical properties of the airway mucus and on the activity of the cilia. The former, in turn, is dependent mainly on the quality and quantity of mucous glycoproteins or mucins, which are produced by two different cell types, namely, goblet cells of the epithelium and mucous cells of the submucosal gland. Neither the structural nor the functional differences of mucins produced by these two cell types are yet known. The availability of primary airway epithelial cell culture systems, however, has made it possible to study the structure and regulation of airway goblet cells to some extent. The epithelial mucins are extremely hydrophobic and are associated with various macromolecules, the quality and quantity of which may also affect the physicochemical properties of the mucus. Secretion of epithelial mucins is stimulated by various factors, including a number of inflammatory agents. The recent progress in mucin molecular biological research will allow us to identify different mucin core proteins produced by those different cell types, and, hopefully, the differential functions of these mucins in health and disease.

Performance characteristics of combined haemodialysis/haemoperfusion system for removal of blood toxins

The application of high clearance haemodialysis (HD) for removal of small molecules of waste metabolites, has been practised for many years. Haemoperfusion (HP) is capable of effective removal of middle and protein-bound molecules. The combined HD/HP system is thought to give a more effective treatment for patients of renal failure or drug intoxication. This paper discusses the performance characteristics of removal of toxic substances (e.g. paraquat and creatinine), using the combined HD/HP recycled system in two different arrangements (HD-HP and HP-HD). The results demonstrate that for most favourable adsorbing solutes, the HD-HP arrangement gives higher performance whereas, HP-HD arrangement is more suitable and gives more effective detoxication characteristics for unfavourable adsorbing solutes.

Anesthetic management in parturients with uterine rupture preoperatively--report of two cases

Uterine rupture is a rare obstetric emergency, and the diagnosis of rupture is not always obvious. High surgical delivery rate today which tends to increase the incidence of the disaster urged us to present this report. Two cases of spontaneous rupture of uterus are described. Case 1 concerns spontaneous rupture of a previously intact uterus; case 2 is a rupture due to placenta percreta. A review relevant to its incidence, risk factors, clinical characteristics, and anesthetic managements is given.

ATP P2X receptors mediate fast synaptic transmission in the dorsal horn of the rat spinal cord

ATP has been proposed to mediate synaptic transmission in the spinal cord dorsal horn, particularly in the pathway carrying nociceptive information. Using transverse spinal cord slices from postnatal rats, we show that EPSCs mediated by P2X receptors, and presumably activated by synaptically released ATP, are evoked in a subpopulation of spinal cord lamina II neurons, a region known to receive strong input from nociceptive primary afferents. The P2X receptors on acutely dissociated dorsal horn neurons are nondesensitizing, insensitive to alphabeta methylene ATP, and show strong but variable sensitivity to the antagonists suramin and pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). These characteristics are consistent with a heterogeneous population of P2X receptors, the composition of which includes P2X2, P2X4, and P2X6 receptor subtypes. Our results suggest that ATP-activated P2X receptors in lamina II of the rat spinal cord may play a role in transmitting or modulating nociceptive information.

Characterization of hemin binding activity of Streptococcus pneumoniae

Streptococcus pneumoniae is a causative agent of bacterial pneumonia, otitis media, meningitis, and bacteremia. It causes considerable morbidity and mortality throughout the world, especially among children, the elderly, and immunocompromised individuals. We have demonstrated previously that the growth of S. pneumoniae is limited under iron-depleted conditions and can be restored by the addition of either hemin or hemoglobin. In the present study, we showed that S. pneumoniae had the ability to bind hemin and that the level of hemin binding activity was not affected by supplementation of the growth medium with iron. Approximately 70 to 80% of the hemin binding activity was mediated by proteinase-resistant components, and the remainder was mediated by proteins. Hemin binding proteins were located in both soluble extract and envelope fractions of pneumococcal cells. By batch affinity chromatography, a major hemin binding polypeptide with an apparent molecular mass of 43 kDa was identified in the cell lysate of S. pneumoniae. Polyclonal antibodies against this polypeptide were raised. By immunoblot analysis, this hemin binding polypeptide was localized in the envelope and did not exhibit any variation in molecular weight among all serotypes tested. The subcellular distribution of hemin binding activity may have functional implications.

Immunologic epitope, gene, and immunity involved in pneumococcal glycoconjugate

Pneumococcal infection persists as a major cause of pneumonia, otitis media, and meningitis in infants. Children less than 2 years of age show the highest incidence of pneumococcal diseases. Production of monoclonal antibody (MAb) to polysaccharide (PS) and binding characteristics to PS epitopes were studied. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in a decreased binding with rabbit 9V antiserum (AS). However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. Type 9V IgG MAb provided passive protection and enhanced the opsonophagocytic activity of polymorphonuclear (PMN) leukocytes to kill type 9V pneumococci. The pathogenecity of pneumococci is attributed to various virulence factors distributed on the cell surface, including capsular polysaccharide and protein antigens, for example, pneumolysin, autolysin, pneumococcal surface protein A (PspA), pneumococcal surface adhesion (PsaA), and hemin binding protein. Some of these protein antigens may be used as a component to combine with pneumococcal PS vaccine or as a carrier of conjugate vaccine. Clinical trials of pneumococcal conjugate vaccines showed that covalent linkage of capsular PS to protein carriers improved the immunogenicity of the PS. Development of glycoconjugate vaccine for selected pneumococcal types will help solve the problem of poor immunogenecity of PS vaccine in young children used for prevention of pneumococcal infection.