Diabetes regulates mitochondrial biogenesis and fission in mouse neurons.

AIMS/HYPOTHESIS: Normal mitochondrial activity is a critical component of neuronal metabolism and function. Disruption of mitochondrial activity by altered mitochondrial fission and fusion is the root cause of both neurodegenerative disorders and Charcot-Marie-Tooth type 2A inherited neuropathy. This study addressed the role of mitochondrial fission in the pathogenesis of diabetic neuropathy. METHODS: Mitochondrial biogenesis and fission were assayed in both in vivo and in vitro models of diabetic neuropathy. Gene, protein, mitochondrial DNA and ultrastructural analyses were used to assess mitochondrial biogenesis and fission. RESULTS: There was greater mitochondrial biogenesis in dorsal root ganglion neurons from diabetic compared with non-diabetic mice. An essential step in mitochondrial biogenesis is mitochondrial fission, regulated by the mitochondrial fission protein dynamin-related protein 1 (DRP1). Evaluation of diabetic neurons in vivo indicated small, fragmented mitochondria, suggesting increased fission. In vitro studies revealed that short-term hyperglycaemic exposure increased levels of DRP1 protein. The influence of hyperglycaemia-mediated mitochondrial fission on cell viability was evaluated by knockdown of Drp1 (also known as Dnm1l). Knockdown of Drp1 resulted in decreased susceptibility to hyperglycaemic damage. CONCLUSIONS/INTERPRETATION: We propose that: (1) mitochondria undergo biogenesis in response to hyperglycaemia, but the increased biogenesis is insufficient to accommodate the metabolic load; (2) hyperglycaemia causes an excess of mitochondrial fission, creating small, damaged mitochondria; and (3) reduction of aberrant mitochondrial fission increases neuronal survival and indicates an important role for the fission-fusion equilibrium in the pathogenesis of diabetic neuropathy.

Identification and characterization of a novel extracellular matrix protein nephronectin that is associated with integrin alpha8beta1 in the embryonic kidney.

The epithelial-mesenchymal interactions required for kidney organogenesis are disrupted in mice lacking the integrin alpha8beta1. None of this integrin's known ligands, however, appears to account for this phenotype. To identify a more relevant ligand, a soluble integrin alpha8beta1 heterodimer fused to alkaline phosphatase (AP) has been used to probe blots and cDNA libraries. In newborn mouse kidney extracts, alpha8beta1-AP detects a novel ligand of 70-90 kD. This protein, named nephronectin, is an extracellular matrix protein with five EGF-like repeats, a mucin region containing a RGD sequence, and a COOH-terminal MAM domain. Integrin alpha8beta1 and several additional RGD-binding integrins bind nephronectin. Nephronectin mRNA is expressed in the ureteric bud epithelium, whereas alpha8beta1 is expressed in the metanephric mesenchyme. Nephronectin is localized in the extracellular matrix in the same distribution as the ligand detected by alpha8beta1-AP and forms a complex with alpha8beta1 in vivo. Thus, these results strongly suggest that nephronectin is a relevant ligand mediating alpha8beta1 function in the kidney. Nephronectin is expressed at numerous sites outside the kidney, so it may also have wider roles in development. The approaches used here should be generally useful for characterizing the interactions of novel extracellular matrix proteins identified through genomic sequencing projects.

Regulation of neurotrophin-3 expression by epithelial-mesenchymal interactions: the role of Wnt factors.

Neurotrophins regulate survival, axonal growth, and target innervation of sensory and other neurons. Neurotrophin-3 (NT-3) is expressed specifically in cells adjacent to extending axons of dorsal root ganglia neurons, and its absence results in loss of most of these neurons before their axons reach their targets. However, axons are not required for NT-3 expression in limbs; instead, local signals from ectoderm induce NT-3 expression in adjacent mesenchyme. Wnt factors expressed in limb ectoderm induce NT-3 in the underlying mesenchyme. Thus, epithelial-mesenchymal interactions mediated by Wnt factors control NT-3 expression and may regulate axonal growth and guidance.

Lack of neurotrophin-3 results in death of spinal sensory neurons and premature differentiation of their precursors.

To understand mechanisms resulting in the absence of two-thirds of spinal sensory neurons in mice lacking NT-3, we have compared dorsal root ganglia development in normal and mutant embryos. The reduction in neurons, achieved by E13, results from several deficits: first, elevated neuronal apoptosis significantly reduces neuronal numbers; second, elevated neurogenesis between E11 and E12, without changes in rates of precursor proliferation or apoptosis, depletes the precursor pool; consequently, the reduced precursor pool prevents increases in neuronal numbers between E12 and E13, when most neurons are born in normal animals. Although deficits occur before final target innervation, we show that NT-3 is expressed at all stages in regions accessible to these neurons or their axons and is only restricted to final targets after innervation.

Characterization of neurotrophin and Trk receptor functions in developing sensory ganglia: direct NT-3 activation of TrkB neurons in vivo.

Spinal sensory ganglia have been shown to contain neuronal subpopulations with different functions and neurotrophin dependencies. Neurotrophins act, in large part, through Trk receptor tyrosine kinases: nerve growth factor (NGF) via TrkA, brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5) via TrkB, and neurotrophin-3 (NT-3) via TrkC. In the present paper, we use antibodies to TrkA, TrkB, and TrkC to characterize their expression patterns and to determine which subpopulations of cells are lost in mice lacking individual neurotrophins or Trk receptors. Despite previous reports of Trk receptor mRNAs in neural crest cells, we detect Trk receptor proteins only in neurons and not in neural crest cells or neuronal precursors. Comparisons of neonatal mice deficient in NT-3 or its cognate receptor TrkC have shown that there is a much greater deficiency in spinal sensory neurons in the former, suggesting that NT-3 may activate receptors in addition to TrkC. Using the same antibodies, we show that, during the major period of neurogenesis, NT-3 is required to maintain neurons that express TrkB in addition to those that express TrkC but is not essential for neurons expressing TrkA. Results also indicate that survival of cells expressing both receptors can be maintained by activation of either one alone. NT-3 can thus activate more than one Trk receptor in vivo, which when coexpressed are functionally redundant.

The integrin receptor alpha 8 beta 1 mediates interactions of embryonic chick motor and sensory neurons with tenascin-C.

This paper identifies a neuronal receptor for tenascin-C (tenascin/cytotactin), an extracellular matrix protein that has previously been detected in developing sensory and motor neuron pathways and has been shown to regulate cell migration in the developing CNS. Antibodies specific for each subunit of the integrin alpha 8 beta 1 are used to demonstrate that alpha 8 beta 1 mediates neurite outgrowth of embryonic sensory and motor neurons on this extracellular matrix protein. In addition, expression of alpha 8 in K562 cells results in surface expression of alpha 8 beta 1 heterodimers that are shown to promote attachment of this cell line to tenascin. The major domain in tenascin that mediates neurite outgrowth is shown to be localized to fibronectin type III repeats 6-8.

Spatial shaping of cochlear innervation by temporally regulated neurotrophin expression.

Previous work suggested qualitatively different effects of neurotrophin 3 (NT-3) in cochlear innervation patterning in different null mutants. We now show that all NT-3 null mutants have a similar phenotype and lose all neurons in the basal turn of the cochlea. To understand these longitudinal deficits in neurotrophin mutants, we have compared the development of the deficit in the NT-3 mutant to the spatial-temporal expression patterns of brain-derived neurotrophic factor (BDNF) and NT-3, using lacZ reporters in each gene and with expression of the specific neurotrophin receptors, trkB and trkC. In the NT-3 mutant, almost normal numbers of spiral ganglion neurons form, but fiber outgrowth to the basal turn is eliminated by embryonic day (E) 13.5. Most neurons are lost between E13.5 and E15.5. During the period preceding apoptosis, NT-3 is expressed in supporting cells, whereas BDNF is expressed mainly in hair cells, which become postmitotic in an apical to basal temporal gradient. During the period of neuronal loss, BDNF is absent from the basal cochlea, accounting for the complete loss of basal turn neurons in the NT-3 mutant. The spatial gradients of neuronal loss in these two mutants appear attributable to spatial-temporal gradients of neurotrophin expression. Our immunocytochemical data show equal expression of their receptors, TrkB and TrkC, in spiral sensory neurons and thus do not relate to the basal turn loss. Mice in which NT-3 was replaced by BDNF show a qualitative normal pattern of innervation at E13.5. This suggests that the pattern of expression of neurotrophins rather than their receptors is essential for the spatial loss of spiral sensory neurons in NT-3 null mutants.

Endogenous brain-derived neurotrophic factor and neurotrophin-3 antagonistically regulate survival of axotomized corticospinal neurons in vivo.

Neuronal growth factors regulate the survival of neurons by their survival and death-promoting activity on distinct populations of neurons. The neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) promote neuronal survival via tyrosine kinase (Trk) receptors, whereas NGF and BDNF can also induce apoptosis in developing neurons through p75(NTR) receptors in the absence of their respective Trk receptors. Using mutant mice and inactivation of neurotrophins and their receptors with antibodies in rats, we show that endogenous NT-3 induces death of adult BDNF-dependent, axotomized corticospinal neurons (CSNs). When NT-3 is neutralized, the neurons survive even without BDNF, suggesting complete antagonism. Whereas virtually all unlesioned and axotomized CSNs express both trkB and trkC mRNA, p75 is barely detectable in unlesioned CSNs but strongly upregulated in axotomized CSNs by day 3 after lesion, the time point when cell death occurs. Blocking either cortical TrkC or p75(NTR) receptors alone prevents death, indicating that the opposing actions of NT-3 and BDNF require their respective Trk receptors, but induction of death depends on p75(NTR) cosignaling. The results show that neuronal survival can be regulated antagonistically by neurotrophins and that neurotrophins can induce neuronal death in the adult mammalian CNS. We further present evidence that signaling of tyrosine kinase receptors of the trk family can be crucially involved in the promotion of neuronal death in vivo.

Optimal teaching environment for laparoscopic splenectomy.

BACKGROUND: Traditional surgical teaching depends on graduated acquisition of skill learned in residency. The introduction of minimal access techniques after residency training has created a new paradigm dependent on animate course experiences and limited preceptor training. The outcome of performance of a new skill "learned" in these settings has not been assessed. The purpose of this study was to test the benefit of an animate course compared with a precepted operating room experience in learning to perform a laparoscopic splenectomy. METHODS: All attending surgeons who had taken a 1-day course to learn laparoscopic splenectomy (n = 37) and those who had undergone an intraoperative preceptorship (in their hospital) by the lead author (n = 15) were polled to ascertain their previous experience with laparoscopy and with laparoscopic splenectomy since the intervention. The course included lectures, operative videos, and an animal lab. Statistical differences were measured using a t test. RESULTS: Thirty-two of the 37 (86.5%) taking the course and all 15 of the precepted surgeons responded. There was no difference between the groups regarding prior laparoscopic experience (P = 0.73), laparoscopic training during residency (P = 0.74), academic or private practice (P = 0.48), or follow-up since the intervention (P = 0.36). The participants graded the courses (1 to 5, 5 = excellent) at an average of 4.72. Fourteen of 15 precepted surgeons have performed laparoscopic splenectomy as compared with 2 of 32 taking courses (nonprecepted surgeons; P <0.0001). The number of laparoscopic splenectomies performed totaled 112 for precepted surgeons and 4 for nonprecepted surgeons (P = 0.0003). The nonprecepted surgeons performed significantly more open splenectomies than laparoscopic (95 versus 13 respectively, P = 0.02). Reasons quoted not to proceed with laparoscopic splenectomy included waiting for the perfect patient, concern of hilar management, and splenic size. CONCLUSION: Surgeons precepted in their own operating room performed a laparoscopic splenectomy more readily than those gaining experience from a course only (93% versus 6%, respectively) despite no difference in their preintervention experience and having the opportunity to do so. The expectation of the eventual performance of advanced laparoscopic techniques depends on a precepted experience.

Prospective randomized evaluation of surgical resident proficiency with laparoscopic suturing after course instruction.

BACKGROUND: Laparoscopic suturing is required to develop competency in advanced laparoscopy. METHODS: Manuals detailing laparoscopic suturing were give to 17 Surgery residents. One week later they performed a suture on a training model. Time (s), accuracy (mm), and knot strength (lb) were recorded. The residents were blindly randomized to intervention (n = 9) and control (n = 8) groups. The intervention residents attended a 60-min course with lecture, video, and individual proctoring. Two weeks later they performed a stitch with standard laparoscopic instruments and a stitch with a suturing assist device. Statistical analysis included a Wilcoxon rank-sum test. RESULTS: The intervention residents decreased their suturing time from the first to the second stitich (732.4-257.6s), the control and residents decreased their time from 500.2 s to 421.8 s. The time required to perform the second stitch showed no significant difference between the two groups (p = 0.46), but the difference in reduced time between the first and second stitch was significant (p = 0.001). Using the suturing assist device for the third suture, the intervention and control groups both decreased their times significantly. The control residents performed almost as quickly as the intervention residents with the suturing; device (p = 0.11). Accuracy and knot strength were not different in any test. CONCLUSIONS: Residents can improve suturing skill with a short didactic course and individual proctoring. A suturing assist device decreases time required by inexperienced surgeons to device perform an intracorporeal tie.

Initial results with an electrothermal bipolar vessel sealer.

BACKGROUND: An electrothermal bipolar vessel sealer (EBVS; Ligasure, Valleylab, Boulder, CO, USA) was developed as an alternative to suture ligatures, hemoclips, staplers, and ultrasonic coagulators for ligating vessels and tissue bundles. The EBVS seals vessels up to 7 mm in diameter by denaturing collagen and elastin within the vessel wall and surrounding connective tissue. This study is the first to determine the clinical efficacy and safety of this instrument and delineate its potential timesavings in both experimental (animal) and clinical scenarios. METHODS: A prospective review of the author's clinical experience with the EBVS in laparoscopic and open operations from October 1998 to March 2000 was performed. In addition, five Yorkshire domestic pigs underwent 150-cm small intestine resections (n = 10) using the EBVS (n = 5) and suture ligatures (n = 5). Measurements included time to complete intestinal resection, the number of applications per minute for each method, and the presence of postapplication bleeding. Statistical analysis was performed using Student's t-test. RESULTS: The EBVS was used in 98 cases (46 laparoscopic and 52 open) with a mean of 43 applications (range, 10-150 applications) per case. The operations included 53 colon and/or small bowel resections (54.1%), 24 fundoplications (24.5%), 12 gastric resections (12.2%), 3 splenectomies, 2 pancreatectomies, 1 adrenalectomy, 1 bilateral salpingo-oopherectomy, 1 pancreatic cyst-jejunostomy, and 1 vagotomy with gastrojejunostomy. In all these cases, the EBVS was intended to be the only means of vessel ligation. An alternative ligation technique was required for bleeding in only 13 (0.3%) of more than 4,200 applications of the EBVS. No postoperative hemorrhagic complications occurred. There was an estimated mean reduction in operative time of 39 min per open procedure, and a mean prolongation in operative time of 8 min per laparoscopic procedure when the EBVS was used in lieu of suture ligatures, hemoclips, staplers, or ultrasonic coagulators. In the animal model, the mean time for completion of the intestinal resection was 251.9 s for the EBVS and 702.0 s for ligatures (p < 0.001). The mean number of applications per minute was 7.6 for the EBVS and 1.8 for ligatures (p < 0.001). No postapplication bleeding was seen. CONCLUSIONS: Initial clinical results from the use of EBVS in laparoscopic and open procedures demonstrate it to be safe and effective, reducing operative time in open procedures. Suture ligatures, ties, hemoclips, and other ligating techniques were used rarely (0.3%) after an application of the EBVS. In an experimental animal model, the EBVS was significantly faster and more efficient (more applications per minute) than ligatures for intestinal resection.

Effectiveness of the ultrasonic coagulating shears, LigaSure vessel sealer, and surgical clip application in biliary surgery: a comparative analysis.

Advancements in laparoscopic surgery are often dictated by the limitations of technical instrumentation. Energy sources other than electrosurgery have become popular with the promise of quick and effective vascular control. With their success surgeons have begun using these on structures other than blood vessels with little or no data establishing their efficacy or safety. This study evaluates alternative energy sources in sealing ductal structures for possible use in liver or gallbladder surgery. After elective cholecystectomy cystic ducts (n = 45) were resealed ex vivo with surgical clips (n = 14), ultrasonic coagulating shears (n = 16), or electrothermal bipolar vessel sealer (n = 15), and bursting pressures were measured. Nineteen additional human cystic ducts were randomized to seal by ultrasonic coagulating shears (n = 9) or electrothermal bipolar vessel sealer (n = 10) and fixed in 10 per cent buffered formalin for histologic evaluation of thermal spread (mm). After this nine adult pigs were randomized to laparoscopic ligation and transection of the common bile duct using surgical clips (n = 3), ultrasonic coagulating shears (n = 3), or electrothermal bipolar vessel sealer (n = 3). The animals underwent necropsy for assessment of seal integrity on the sixth postoperative day. In the ex vivo study the mean cystic duct bursting pressure was 621 mm Hg with surgical clips and 482 mm Hg with the electrothermal bipolar vessel sealer (P = 0.39). The mean cystic duct bursting pressure after ultrasonic coagulating shears was 278 mm Hg, which was statistically less than surgical clips (P = 0.007) and electrothermal bipolar vessel sealer (P = 0.02). The mean thermal spread was 3.5 mm for ultrasonic coagulating shears and 13.4 mm for electrothermal bipolar vessel sealer (P = 0.0002). All animals undergoing ligation and transection of the common bile duct with ultrasonic coagulating shears and electrothermal bipolar vessel sealer developed bile peritonitis by postoperative day 6 as a result of seal leak. All animals undergoing surgical clip ligation and transection of the common bile duct maintained seal integrity. The mean common bile duct pressure above the surgical clip was 12 mm Hg (range 10-14). In conclusion the acute ex vivo study demonstrated a significant difference in the cystic duct bursting pressure between surgical clips and ultrasonic coagulating shears and between electrothermal bipolar vessel sealer and ultrasonic coagulating shears. The ultrasonic coagulating shears and electrothermal bipolar vessel sealer failed to maintain seal integrity in the in vivo animal study. Given the failure of the ultrasonic coagulating shears and electrothermal bipolar vessel sealer in the animal model these energy sources should not be used for transection of the cystic duct or major hepatic ducts during hepatobiliary surgery.

Optimal teaching environment for laparoscopic ventral herniorrhaphy.

The introduction of laparoscopic techniques after residency training has created a new paradigm dependent on laparoscopic workshops. This study tested the benefit of an animate course and evaluated the role of proctoring in learning to perform laparoscopic ventral hernia repair (LVHR). Surgeons who had taken a 1-day LVHR course (n = 59) were polled to determine previous experience with laparoscopic procedures and experience with LVHR after the course. Forty-eight (81%) surgeons completing the course responded. Thirty-two (67%) surgeons had performed 179 LVHRS (mean 5.6) since the course. There were no statistically significant differences between the groups performing and not performing LVHR regarding academic/private practice (P=0.8) or opportunities to perform a ventral herniorrhaphy (P = 0.6). Fifteen (31%) surgeons were precepted in their hospital operating room by the lead author. Thirteen (87%) of precepted surgeons had performed a LVHR compared with 19 (58%) of the 33 surgeons taking the course without a precepted intervention (P = 0.05). Surgeons with experience performing laparoscopic inguinal hernia repair, Nissen fundoplication, and common bile duct exploration were more likely to perform LVHR (P=0.0001). Surgeons performing only laparoscopic cholecystectomy tended to be less likely to perform LVHR, nearing statistical significance (P=0.08). Surgeons with prior advanced laparoscopic surgery experience are thus more likely to perform LVHR after participating in a 1-day course. Surgeons precepted in their hospital operating room were also more likely to perform LVHR. Participation in an animate laboratory and a precepted experience can impact the future performance of advanced laparoscopic surgery.

Clearance of exogenous carnitine in bovine semen: Potential diagnosis of epididymal function and patency of the ductus deferens.

Carnitine content in the ejaculate depends mainly on the capability of the epididymis wall to transfer carnitine from the blood and on the patency of ejaculatory ductus systems. An elevation of carnitine in semen subsequent to an intravenous injection of carnitine is expected. Intravenous injections of carnitine (L-isomer and DL-isomers) caused a significant (P <0.05) elevation (more than 10-fold) in blood carnitine. However, carnitine injection failed to increase net secretion of carnitine into the ejaculate and blood elimination half-life was 2.3 hours. Mean concentrations of carnitine in the electroejaculate (3.0 nmoles/ml) were significantly lower than in the ejaculate following natural mating (180 nmoles/ml). Vasectomy decreased net carnitine per ejaculate to about 1/5 the prevasectomy value, when ejaculate was collected following natural mating. However, vasectomy did not affect carnitine concentrations in semen collected by electroejaculation. Twenty-one percent of the carnitine in semen originated in the accessory glands and 79% in the epididymides. Carnitine in the electroejaculate was originated almost exclusively in the accessory glands. It was concluded that the diagnostic value of carnitine in semen is limited. Some considerations are: secretion of carnitine is not organ specific, there are large individual variations, there is a negative effect of electroejaculation, and a carnitine loading dose technique is not feasible. However, there is a diagnostic potential in using carnitine assay to detect epididymides occlusion, but only when ejaculate is collected by an artificial vagina.

Mini-laparoscopic splenectomy.

BACKGROUND AND PURPOSE: Since the introduction of mini-laparoscopic instruments (2- to 3-mm diameter), their utility and safety have been questioned. Their application in cholecystectomy has recently been documented. This study determined the adequacy and safety of these minimally invasive instruments in laparoscopic splenectomy. METHODS: Retrospective review of all 16 mini-laparoscopic splenectomies performed by the authors was carried out. Diagnoses included immune thrombocytopenia (5), spherocytosis (6), and beta-thalassemia, sickle-cell disease, splenic mass, cyst, and splenomegaly in 1 case each. The average age of the patients was 20.1 years (range 4-70 years); seven patients were adults. Ten of the patients were female. The patients' body mass index ranged from 17 to 25 kg/m2. Splenomegaly (at least two times normal size: 100-200 g for children, 400-600 g for adults) was present in each case. A three-trocar technique was used in 15 patients, and a fourth trocar was required in only one case. RESULTS: The average operative time and blood loss were 114 minutes (range 60-195 minutes) and 44 mL (range 10-150 mL), respectively. There were no intraoperative complications, and no patient required transfusion. Conversion to standard laparoscopy or laparotomy did not occur. The mean hospital stay was 1.4 days (range 1-2 days). With an average 20-month follow-up, no wound, septic, or other complications have been identified. All patients or their families (in the case of children) graded the cosmetic outcome as excellent. CONCLUSION: The use of mini-laparoscopic instruments for splenectomy is safe and effective in children and adults with a normal body mass index, even in the case of splenomegaly. Operative times are reasonable, and hospital stays are brief. The postoperative cosmetic appearance is excellent.

Laparoscopic repair of the leaking percutaneous endoscopic gastrostomy.

Peritonitis is an infrequent yet major complication of a percutaneous endoscopic gastrostomy (PEG). Traditionally, patients with peritonitis from leaking PEG tubes underwent open abdominal exploration with repair of the gastrostomy site. We report successful laparoscopic treatment of this significant complication. Surgical techniques and technical aspects of the procedure are discussed.

Passage of exogenous L-thyroxine and triiodothyronine into bovine ejaculate.

The metabolic effects of thyroxine (T4) and triiodothyronine (T3) on spermatozoa metabolism and male anatomy have been demonstrated. The metabolic effects of T3 and T4 could affect the physiologic characteristics of the spermatozoa. There are little data on the passage of T4 and T3 into the ejaculate from blood. The passage of exogenous T4 and T3 from the blood into semen was measured after T4 (45 mg) or T3 (37.5 mg) was injected IV into 8 bulls. Blood and electroejaculate were obtained simultaneously at 20, 40, 60, 120, and 180 minutes and 24 hours after bulls were injected to determine T3 and T4 concentrations compared with base-line values. Blood T3 and T4 concentrations were increased (P less than 0.05) at 20 minutes after bulls were injected (1.1 +/- 0.25 to 598 +/- 76.3 ng/ml and from 66 +/- 5 to 1,318 +/- 105 ng/ml, respectively). Seminal concentrations of T4 were unchanged until 120 minutes after bulls were injected, when they increased (P less than 0.05) from less than 1.2 ng/ml to 4.7 +/- 1.9 ng/ml. However, seminal concentrations of T3 were increased (P less than 0.05) from less than 0.1 ng/ml to 0.5 +/- 0.2 ng/ml at 20 minutes and to 12.5 +/- 2.9 ng/ml at 120 minutes after bulls were injected. It was concluded that exogenous thyroid hormones passed into the ejaculate from blood, with T3 passing faster than T4.

Effect of electroejaculation on progesterone and cortisol excretion in bovine semen.

Artificial vagina (AV) and electroejaculation (EE) are the 2 methods used to obtain semen from bulls. The purpose in the present study was to evaluate these 2 methods of collection when 2 markers, cortisol and progesterone, were injected IV. During period 1 (control measurement), semen was obtained by EE at 0, 20, 60, 120, and 180 minutes. In period 2, bulls were injected (3 days later) with a mixture of cortisol (113 mg) and progesterone (100 mg), and then samples were obtained by EE. In period 3, cortisol and progesterone were injected (3 weeks later), and samples were obtained by AV. Seminal plasma concentrations of cortisol and progesterone were maximal at 20 minutes in EE and AV collections. Seminal plasma concentrations of progesterone and cortisol were roughly 50% less in EE than in AV collection. However, the total excretion of progesterone and cortisol per collection was similar in both techniques. Excretion of cortisol was 14 to 33 times greater than that of progesterone. It was concluded that concentrations of markers in the EE were significantly less than those in AV collection. For this reason, total excretion and concentration of marker in semen should be accounted for when conducting excretion studies.

Uterotonic effect of prostaglandin F2 alpha and oxytocin on the postpartum cow.

Uterine motility was measured in 6 mixed-breed beef cows 48 to 72 hours after parturition, using an intrauterine balloon technique. Baseline uterine motility was measured for 30 minutes after a stabilization period. After 25 mg of prostaglandin F2 alpha (PGF2 alpha) was given IM, motility was recorded for 2 to 4 hours. After PGF2 alpha injection, 200 IU of oxytocin was given IM and motility was recorded for 2 to 4 hours. Twenty-four hours later, oxytocin treatment was administered, and 2 to 4 hours later, PGF2 alpha was given. The tension-time index was calculated. When PGF2 alpha was given initially, it did not affect (P greater than 0.05) uterine motility. However, oxytocin after PGF2 alpha increased uterine motility an average of about 225% of that of base line 20 minutes after injection. When oxytocin was given before PGF2 alpha treatment, the average increment of uterine motility was 875% above base line 20 minutes after oxytocin injection. The injection of PGF2 alpha did not affect uterine motility significantly (P greater than 0.05), whether given before or after oxytocin treatment. There was a linear decrease in the uterotonic effect of oxytocin between 10 minutes and 2 hours. When oxytocin was injected first, the correlation coefficient for the time-response relationship was -0.98. When oxytocin was injected after PGF2 alpha, the correlation coefficient was -0.84. Seemingly, PGF2 alpha should not be used as a uterotonic agent in the postpartum cow; however, oxytocin was an effective uterotonic agent.

Spirituality of EMTs: a study of the spiritual nature of EMS workers and its effects on perceived happiness and prayers for patients.

INTRODUCTION: There is reason to believe that traumatic events experienced on the job make emergency medical services (EMS) workers more skeptical about their spiritual beliefs. Little is known about the spiritual lives and experiences of emergency medical technicians (EMTs). No studies have measured the responses of EMTs to the spiritual needs of their patients. PURPOSE: This study investigates whether EMS workers are less spiritual than the average U.S. citizen, and what effect this has on prayer for patients and perceived happiness. METHODS: Data were collected in a major metropolitan EMS system from 125 EMTs and paramedics through a questionnaire about their beliefs and behaviors regarding their spirituality. Pearson product-moment correlation coefficients (r) were used to analyze variables. The religious attitudes of EMTs were compared with those of the general population as defined in the Gallup studies. RESULTS: Ninety-one percent of the EMS workers interviewed and 94% of Gallup's sample of the general population said they believe in God. The findings on other measures in the EMT sample also were very similar to those defined in the general population. Of the EMTs, 60% said they never have doubted the existence of God. Eighty-four percent believe God still works miracles, and 80% of the EMTs believe in life after death. Eighty-seven percent of EMS workers pray; 62% pray for their patients, and 54% pray for their coworkers. Frequency of church or synagogue attendance is positively and significantly correlated with the degree of perceived life happiness (r = 0.226, p < 0.025 > 0.005). Frequency of prayer also is correlated positively to perceived life happiness (r = 0.182, p < 0.025 > 0.005). CONCLUSION: Emergency medical services workers are interested and willing to talk about their spiritual lives. They do have more doubts about the existence of God than does the average civilian, but are just as spiritual. Those EMTs with more active spiritual lives perceive themselves as happier. The majority of EMS workers pray for their patients.