Tyrosine phosphatase-dependent/tyrosine kinase-independent induction of nuclear factor-kappa B by tumor necrosis factor-alpha: effects on prostaglandin endoperoxide synthase-2 mRNA accumulation

We previously have demonstrated that tumor necrosis factor-alpha (TNF-alpha) increases prostaglandin endoperoxide synthase-2 (PGHS-2) mRNA accumulation and tyrosine phosphorylation in the fibrosarcoma cell line, MCA-101. Tyrosine kinase inhibitor, genistein, and tyrosine phosphatase inhibitor, phenylarsine oxide (PAO), blocked TNF-alpha-mediated induction of PGHS-2 mRNA in these cells. Because the PGHS-2 promoter has a nuclear factor-kappa B (NF-kappa B) binding motif, which is important for PGHS-2 gene transcription in some cell types, we have evaluated the effects of tyrosine kinase inhibitors and PAO on TNF-alpha-induced NF-kappa B activation. TNF-alpha (1 nM) rapidly induced translocation of NF-kappa B, an event accompanied by degradation of inhibitory protein I kappa B-alpha. N-tosyl-L-phenylalanine chloromethyl ketone (TPCK), a serine protease inhibitor, inhibited I kappa B-alpha degradation and NF-kappa B activation in response to TNF-alpha in a dose-dependent manner (25, 50, 100 microM). TPCK also inhibited PGHS-2 mRNA accumulation. These data suggest that NF-kappa B contributed to PGHS-2 mRNA accumulation in MCA-101 cells stimulated with TNF-alpha. PAO (2.4 microM) completely abolished activation of NF-kappa B and degradation of I kappa B-alpha induced by TNF-alpha at a concentration that blocked PGHS-2 mRNA accumulation. However, four tyrosine kinase inhibitors, genistein, tyrphostin 47, herbimycin A and erbstatin, failed to block translocation of NF-kappa B and degradation of I kappa B-alpha. These data demonstrate that tyrosine kinase pathways are not required for TNF-alpha-induced NF-kappa B activation in MCA-101 cells and suggest that signaling via these pathways mediates TNF-alpha-induced PGHS-2 mRNA accumulation via an NF-kappa B-independent mechanism. Moreover, an upstream tyrosine phosphatase pathway may mediate PGHS-2 mRNA accumulation by TNF-alpha via an NF-kappa B-dependent mechanism.

Bioactive and immunoreactive FSH concentrations in ewe and ram lambs over the first year of life

Several studies suggest that the concentration of immunoreactive (I) FSH measured in peripheral plasma by radioimmunoassay does not always reflect the level of bioactive (B) hormone capable of eliciting a biological response (e.g. oestradiol synthesis by Sertoli cells in vitro). The aim of this study was to measure both B-FSH and I-FSH concentrations in male and female sheep during the first year of life, and to relate this to pubertal development. The hypothesis being tested was that B-FSH is present in both male and female sheep during the prepubertal period and that discrete changes in B-FSH are associated with the onset of puberty. Eight ewe lambs and eight rams lambs were blood sampled fortnightly form 2 to 52 weeks of age. All samples were assayed for B-FSH content. Pubertal development was monitored in ewe lambs from behavioural oestrus and from plasma progesterone concentrations, and in ram lambs from penile and testicular development and from plasma testosterone concentrations. Mean I-FSH concentrations varied significantly with time after birth, in both females and males (P < 0.01). In contrast, B-FSH was found to vary with time in females only (P < 0.01). Around the expected time of puberty in ram lambs (i.e. at 30-40 weeks of age), and thereafter, I-FSH concentrations were undetectable (< 0.2 ng ml-1), whereas the B-FSH concentrations were measurable at concentrations up to twice the assay detection limit (0.8 ng ml-1) until 38 weeks of age. In ewe lambs, but not ram lambs, there was a significant linear relationship between B-FSH and I-FSH values (R = 0.595; P < 0.005). When standardised about the time of puberty, B-FSH (P < 0.05) but not I-FSH was significantly higher in ewe lambs that failed to reach puberty. No differences for either B-FSH or I-FSH between pubertal and non-pubertal ram lambs were noted. In summary, B-FSH was soften measurable in plasma throughout prepubertal development in sheep and the concentrations often differed from those of I-FSH, especially in ram lambs. However, there appeared to be no discrete change in B-FSH that could be directly related to specific pubertal events. It is concluded that although FSH may be a prerequisite for prepubertal testicular development and/or ovarian follicular growth, it is not a critical factor in determining whether puberty is attained during the first year of life in this seasonally breeding species.

Tumour necrosis factor-alpha-dependent regulation of prostaglandin endoperoxide synthase-2

Tumour necrosis factor alpha (TNF-alpha)-mediated regulation of prostaglandin endoperoxide synthase-2 (PGHS-2) mRNA levels was examined in murine fibrosarcoma MCA-101 cells. We demonstrated that the formation of prostaglandin E2 (PGE2) is highly dependent on the expression of PGHS-2 enzyme in these cells. TNF-alpha-induced PGE2 production was evident after 12 h and was associated with a significant TNF-alpha-mediated increase in PGHS-2 immunoreactive protein. A specific PGHS-2 inhibitor, NS-398, completely abolished the TNF-alpha-mediated increase in PGE2 production, suggesting that the PGE2 formed in response to TNF-alpha was derived from PGHS-2. TNF-alpha-mediated PGHS-2 mRNA accumulation was observed at 1 h, remained elevated for 24 h, and was blocked by actinomycin D, indicating that TNF-alpha increases PGHS-2 gene transcription. A significant post-transcriptional mechanism also contributed to the increased PGHS-2 mRNA accumulation as the mRNA half-life was approximately 4-5 h in TNF-alpha-stimulated cells. Inhibition of protein tyrosine phosphatases (PTPs) and protein tyrosine kinases (PTKs) inhibited the TNF-alpha-mediated increase in PGHS-2 mRNA levels. We suggest that PTPs and PTKs play a role in the transcriptional and/or post-transcriptional mechanisms that contribute to the regulation of the PGHS-2 gene by TNF-alpha.

Endogenous repair after spinal cord contusion injuries in the rat

Contusion injuries of the rat thoracic spinal cord were made using a standardized device developed for the Multicenter Animal Spinal Cord Injury Study (MASCIS). Lesions of different severity were studied for signs of endogenous repair at times up to 6 weeks following injury. Contusion injuries produced a typical picture of secondary damage resulting in the destruction of the cord center and the chronic sparing of a peripheral rim of fibers which varied in amount depending upon the injury magnitude. It was noted that the cavities often developed a dense cellular matrix that became partially filled with nerve fibers and associated Schwann cells. The amount of fiber and Schwann cell ingrowth was inversely related to the severity of injury and amount of peripheral fiber sparing. The source of the ingrowing fibers was not determined, but many of them clearly originated in the dorsal roots. In addition to signs of regeneration, we noted evidence for the proliferation of cells located in the ependymal zone surrounding the central canal at early times following contusion injuries. These cells may contribute to the development of cellular trabeculae that provide a scaffolding within the lesion cavity that provides the substrates for cellular infiltration and regeneration of axons. Together, these observations suggest that the endogenous reparative response to spinal contusion injury is substantial. Understanding the regulation and restrictions on the repair processes might lead to better ways in which to encourage spontaneous recovery after CNS injury.

An evaluation of the specificity, validity and reliability of jumping tests

BACKGROUND

There were three objectives of this study: 1. To describe the influence of using a single and double leg take-off as a function of run-up length in jumping for height. 2. To determine if various types of jumps are specific in nature. 3. To evaluate two methods of assessing jumping height (a modified Vertec or Yardstick and a Board) for validity and inter-day reliability.

METHODS

Seventeen male subjects were tested on jumps for height from a standing position and using a 1, 3, 5 and 7 stride run-up. These jumps were performed using a single and double leg take-off measured by the Yardstick. Selected jumps were also tested using a Board method and repeated for assessment of reliability.

RESULTS

The single leg take-off produced significantly higher jumps when the run-up was three or more strides. The inter-relationships among jump conditions were generally high, however jump types could be considered as specific when the run-up length and number of legs used in the take-off were different. The Yardstick produced significantly greater jump heights than the Board method, which questions the validity of using a board for assessment of maximum jump performance. The reliability of both methods was generally high however the jumps performed from a run-up produced less reliable results than the standing jumps for the Yardstick.

CONCLUSIONS

It was suggested that the design of tests to assess jumping ability should consider the specific jump type used in the sport of interest and that the Yardstick is the preferred mode of testing, provided that attempts are made to maximise reliability.

Calcium-mediated intracellular messengers modulate the serotonergic effects on axonal excitability

We carried out experiments to investigate the mechanisms of serotonin-induced axonal excitability changes using isolated dorsal columns from young (seven to 11-day-old) Long-Evan's hooded rats. Conducting action potentials were activated by submaximal (50%) and supramaximal constant current electrical stimuli and recorded with glass micropipette electrodes. In experiment 1, to study Ca(2+)-mediated mechanisms, we superfused the preparations with Ringer solutions containing varying Ca2+ concentrations. Following superfusion with Ca(2+)-free Ringer solution for 4 h, we tested initial responses to serotonin agonists. Studies then were repeated after preparations had been washed for 1 h with Ringer solution containing 1.5 mM Ca2+ and 1.5 mM Mg2+. After 4 h superfusion of Ca(2+)-free Ringer solution, quipazine (a serotonin2A agonist, 100 microM) did not induce significant axonal excitability changes (amplitude change of 1.4 +/- 1.3%, percentage of predrug control level, +/-S.D., n = 6). A 100 microM concentration of 8-hydroxy-dipropylaminotetralin (a serotonin1A agonist) reduced response amplitudes by 36.3 +/- 4.2% (+/-S.D., P < 0.0005, n = 7) and prolonged latencies by 22.3 +/- 4.3% (+/-S.D., P < 0.0005, n = 7). Application of serotonin (100 microM) decreased amplitudes by 6.6 +/- 5.0% (+/-S.D., P < 0.05, n = 6). Extracellular calcium concentration ([Ca2+]e) was measured at various depths in the dorsal column with ion-selective microelectrodes. Four hours' superfusion with Ca(2+)-free Ringer solution reduced [Ca2+]e to less than 0.1 mM in dorsal columns. In 1.5 mM Ca2+ Ringer solution, quipazine increased the amplitudes by 38.3 +/- 5.8% (P < 0.0005, n = 6). Likewise, serotonin increased the amplitudes by 13.8 +/- 4.9% (P < 0.005, n = 6). In contrast however, 8-hydroxy-dipropylaminotetralin still reduced amplitudes by 35.0 +/- 6.4% (P < 0.0005, n = 7) and prolonged latencies by 24.1 +/- 4.5% (P < 0.0005, n = 7). In experiment 2, we investigated calcium-dependent and cAMP-mediated protein kinase signalling pathways to evaluate their role as intracellular messengers for serotonin2A receptor activation. Two protein kinase inhibitors, 50 microM H7 (an inhibitor of protein kinase C and c-AMP dependent protein kinase) and 100 microM D-sphingosine (an inhibitor of protein kinase A and C) effectively eliminated the excitatory effects of the serotonin2A agonist. 100 microM cadmium (a Ca2+ channel blocker) also blocked the effects of quipazine. Neither these protein kinase inhibitors nor cadmium alone affected action potential amplitudes. These results suggest that replacing Ca2+ with Mg2+ blocks the excitatory effects of quipazine but does not prevent the inhibitory effects of 8-hydroxy-dipropylaminotetralin, and calcium-mediated protein kinase mechanisms modulate axonal excitability changes induced by serotonin and its agonist.

Evidence for serotonin sensitivity of adult rat spinal axons: studies using randomized double pulse stimulation

We have recently shown both inhibitory and excitatory effects of serotonin on neonatal rat dorsal column axons. While neonatal rat dorsal column axons also respond to norepinephrine and GABA, adult rat dorsal columns are insensitive to the actions of both compounds. Therefore, we studied the effects of serotonin agonists on adult rat dorsal column axons using randomized double pulse stimuli at 0.2 Hz with random interpulse intervals of 3, 4, 5, 8, 10, 20, 30, 50 and 80 ms. The serotonin(1A) agonist, 8-hydroxy-dipropylaminotetralin-hydrobromide (8-OH-DPAT), significantly modulated test response amplitudes at 3, 4, 5 and 8 ms interpulse intervals by 29.6+/-4.0%, 17.4+/-2.1%, 9.6+/-2.3%, and 12.4+/-2.2% of conditioning pulse amplitudes, respectively. The mean latencies at 3, 4 and 5 ms interpulse intervals increased by 17.0+/-5.1%, 8.6+/-2.1%, and 5.1+/-1.4%, respectively (P<0.05). However, neither 10 microM 8-OH-DPAT nor 100 microM serotonin hydrochloride affected the compound action potentials evoked by conditioning or test pulses. In contrast, treatment with 100 microM quipazine dimaleate (a serotonin(2A) agonist) decreased the refractory period. While the response amplitudes to a 3-ms double pulse were reduced by 11.0+/-1.5% during the control period, the test response fell to only 2.4+/-1.8% of the conditioning response amplitudes after exposure to 100 microM quipazine. 8-OH-DPAT decreased the amplitude, prolonged the latency and increased the refractory periods of compound action potentials in the adult rat dorsal column, although a high concentration of the agonist (100 microM) was required for these effects. In contrast, the serotonin(2A) agonist, quipazine, decreased refractory periods. These results suggest that both serotonin(1A) and serotonin(2A) receptor subtypes are present on adult spinal dorsal column axons. Further, these receptors have opposing effects on axonal excitability, despite the fact that their sensitivities are relatively low.

Xenotransplantation of transgenic oligodendrocyte-lineage cells into spinal cord-injured adult rats

Spinal cord trauma is associated not only with loss of nerve cells and fibers but also with damage to oligodendrocytes and demyelination. In order to assess the potential of transplanted oligodendrocyte-lineage cells to repair the demyelination that follows spinal cord injury, we have used donor glia derived from a transgenic mouse line containing the LacZ transgene under control of the myelin basic protein promoter. Glia derived from fetal or neonatal transgenic mice were injected into the spinal cords of immunosuppressed adult rats at the site of an experimental traumatic lesion 1-16 days after injury. Cells expressing LacZ were identified 15-18 days later in cryosections rostral and caudal to the transplant site, most conspicuously within white matter defects. Some of these cells within the dorsal columns gave rise to approximately 30- to 60-microns processes, consistent with myelin segments, which are oriented parallel to the fiber tract. Glial transplantation may thus be a feasible means of replacing damaged host oligodendrocytes with donor oligodendrocyte-lineage cells capable of reforming myelin and potentially restoring functional lost as a result of demyelination associated with spinal cord injury.

Induction of prostaglandin endoperoxide synthase-2 by serine-threonine phosphatase inhibition

Regulation of prostaglandin endoperoxide synthase-2 (PGHS-2) mRNA levels by serine-threonine phosphatases was examined in murine fibrosarcoma methylcholanthrene-101 cells. Okadaic acid (OA), a serine-threonine phosphatase inhibitor, induced PGE2 production and a significant increase in PGHS-2 immunoreactive protein. A specific PGHS-2 inhibitor, N-(2-cyclohexyloxy-4-nitrophenyl) methanesulphonamide, completely abolished the OA-mediated increase in PGE2 production, which suggests that the PGE2 formed in response to OA was derived from PGHS-2. OA-mediated PGHS-2 mRNA accumulation was observed at 1 hr, remained elevated for 24 hr and was blocked by actinomycin D, which indicates that OA increases PGHS-2 gene transcription. A significant post-transcriptional mechanism also contributed to the increased PGHS-2 mRNA accumulation, because the mRNA half-life was approximately 4 to 5 h in OA-stimulated cells. Tumor necrosis factor-alpha, but not OA, activated transcription factor nuclear factor-kappaB in methylcholanthrene-101 cells, as demonstrated by translocation of the nuclear factor-kappaB complex to the nucleus and disappearance of the cytoplasmic inhibitory protein, IkappaB-alpha. We conclude that inhibition of serine-threonine phosphatases contributes to the up-regulation of PGHS-2 expression in an NF-kappaB-independent manner.

Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study

OBJECTIVE

To compare the efficacy of methylprednisolone administered for 24 hours with methyprednisolone administered for 48 hours or tirilazad mesylate administered for 48 hours in patients with acute spinal cord injury.

DESIGN

Double-blind, randomized clinical trial.

SETTING

Sixteen acute spinal cord injury centers in North America.

PATIENTS

A total of 499 patients with acute spinal cord injury diagnosed in National Acute Spinal Cord Injury Study (NASCIS) centers within 8 hours of injury.

INTERVENTION

All patients received an intravenous bolus of methylprednisolone (30 mg/kg) before randomization. Patients in the 24-hour regimen group (n=166) received a methylprednisolone infusion of 5.4 mg/kg per hour for 24 hours, those in the 48-hour regimen group (n=167) received a methylprednisolone infusion of 5.4 mg/kg per hour for 48 hours, and those in the tirilazad group (n=166) received a 2.5 mg/kg bolus infusion of tirilazad mesylate every 6 hours for 48 hours.

MAIN OUTCOME MEASURES

Motor function change between initial presentation and at 6 weeks and 6 months after injury, and change in Functional Independence Measure (FIM) assessed at 6 weeks and 6 months.

RESULTS

Compared with patients treated with methylprednisolone for 24 hours, those treated with methylprednisolone for 48 hours showed improved motor recovery at 6 weeks (P=.09) and 6 months (P=.07) after injury. The effect of the 48-hour methylprednisolone regimen was significant at 6 weeks (P=.04) and 6 months (P=.01) among patients whose therapy was initiated 3 to 8 hours after injury. Patients who received the 48-hour regimen and who started treatment at 3 to 8 hours were more likely to improve 1 full neurologic grade (P=.03) at 6 months, to show more improvement in 6-month FIM (P=.08), and to have more severe sepsis and severe pneumonia than patients in the 24-hour methylprednisolone group and the tirilazad group, but other complications and mortality (P=.97) were similar. Patients treated with tirilazad for 48 hours showed motor recovery rates equivalent to patients who received methylprednisolone for 24 hours.

CONCLUSIONS

Patients with acute spinal cord injury who receive methylprednisolone within 3 hours of injury should be maintained on the treatment regimen for 24 hours. When methylprednisolone is initiated 3 to 8 hours after injury, patients should be maintained on steroid therapy for 48 hours.

Administration of methylprednisolone for 24 or 48 hours or tirilazad mesylate for 48 hours in the treatment of acute spinal cord injury. Results of the Third National Acute Spinal Cord Injury Randomized Controlled Trial. National Acute Spinal Cord Injury Study

OBJECTIVE

To compare the efficacy of methylprednisolone administered for 24 hours with methyprednisolone administered for 48 hours or tirilazad mesylate administered for 48 hours in patients with acute spinal cord injury.

DESIGN

Double-blind, randomized clinical trial.

SETTING

Sixteen acute spinal cord injury centers in North America.

PATIENTS

A total of 499 patients with acute spinal cord injury diagnosed in National Acute Spinal Cord Injury Study (NASCIS) centers within 8 hours of injury.

INTERVENTION

All patients received an intravenous bolus of methylprednisolone (30 mg/kg) before randomization. Patients in the 24-hour regimen group (n=166) received a methylprednisolone infusion of 5.4 mg/kg per hour for 24 hours, those in the 48-hour regimen group (n=167) received a methylprednisolone infusion of 5.4 mg/kg per hour for 48 hours, and those in the tirilazad group (n=166) received a 2.5 mg/kg bolus infusion of tirilazad mesylate every 6 hours for 48 hours.

MAIN OUTCOME MEASURES

Motor function change between initial presentation and at 6 weeks and 6 months after injury, and change in Functional Independence Measure (FIM) assessed at 6 weeks and 6 months.

RESULTS

Compared with patients treated with methylprednisolone for 24 hours, those treated with methylprednisolone for 48 hours showed improved motor recovery at 6 weeks (P=.09) and 6 months (P=.07) after injury. The effect of the 48-hour methylprednisolone regimen was significant at 6 weeks (P=.04) and 6 months (P=.01) among patients whose therapy was initiated 3 to 8 hours after injury. Patients who received the 48-hour regimen and who started treatment at 3 to 8 hours were more likely to improve 1 full neurologic grade (P=.03) at 6 months, to show more improvement in 6-month FIM (P=.08), and to have more severe sepsis and severe pneumonia than patients in the 24-hour methylprednisolone group and the tirilazad group, but other complications and mortality (P=.97) were similar. Patients treated with tirilazad for 48 hours showed motor recovery rates equivalent to patients who received methylprednisolone for 24 hours.

CONCLUSIONS

Patients with acute spinal cord injury who receive methylprednisolone within 3 hours of injury should be maintained on the treatment regimen for 24 hours. When methylprednisolone is initiated 3 to 8 hours after injury, patients should be maintained on steroid therapy for 48 hours.

Feasibility study for use of brush cytology as a complementary method for diagnosis of rectal cancer

Brush cytology has previously been described as a feasible method for accurately diagnosing colorectal cancer.

PURPOSE

This study was designed: 1) to determine the sensitivity and specificity of brush cytology for the diagnosis of rectal cancer; 2) to prospectively assess the extent of interobserver variability with this technique; 3) to prospectively examine the cost impact of the addition of brush cytology as a routine method of confirming the diagnosis of rectal cancer.

PATIENTS AND METHODS

Three hundred fifty-seven patients who attended a rectal clinica and who were found to have a lesion between January 1990 and March 1996 were assessed. Each patient underwent rigid proctoscopy, followed by brush cytology and tissue biopsy. Results were compared with the final histologic diagnosis in each patient. The brushings from the last 92 consecutive patients in this series were independently examined by four cytologists and a pathologist to determine the rate of interobserver variability.

RESULTS

Rectal adenocarcinoma was confirmed from surgically resected specimens in 303 patients. Brush cytology accurately diagnosed 278 of them. Of the remaining 25 patients, two had brushings that were insufficient for diagnosis. There was one false-positive case. Forceps biopsy correctly identified cancer in 260 patients, with no false-positive interpretations. Brush cytology accurately identified 53 of 54 adenomas as being benign, and forceps biopsy correctly identified all as benign. Sensitivity of brush cytology in this series was 92 percent, with a specificity of 92 percent. Interobserver agreement was 84 percent. Actual costs incurred with this method was an additional $17.00 per patient.

CONCLUSIONS

Brush cytology can accurately diagnose rectal cancer in a high proportion of patients. Interobserver variation is low and compares favorably with other forms of cytologic interpretation. The additional cost remains a concern but can be kept within acceptable proportion.

Laparoscopically assisted vaginal hysterectomy. A review of current issues

A review of 39 articles found no consensus on indication for laparoscopic assisted vaginal hysterectomy (LAVH) compared with traditional approaches. Since only three randomized trials comparing LAVH with traditional methods exist, the scientific basis for surgical choice is lacking. Uncontrolled studies indicated that outcomes following LAVH were not superior to vaginal hysterectomy and costs were significantly higher.

Follicle-stimulating hormone in the brushtail possum (Trichosurus vulpecula): purification, characterization, and radioimmunoassay

Follicle-stimulating hormone (FSH) was purified from brushtail possum (Trichosurus vulpecula) pituitary glands by using the following purification techniques: fractional ammonium sulfate precipitation, triazinyl-dye affinity chromatography, hydrophobic interaction chromatography, and gel filtration. A yield of 18 micrograms of FSH per gram of pituitary, with a recovery of 12%, was obtained from 1400 glands (20.3 g wet weight). The purified FSH activity per gram of protein was 1320 times more potent than the initial pituitary homogenate. Contamination with possum luteinizing hormone (LH) was < 0.02%. The amino acid composition of possum FSH was similar to that of ovine FSH. Amino-terminal sequencing for 11 cycles indicated that the alpha subunit has the same sequence as ovine FSH except for residue 7, where the possum FSH alpha subunit contains isoleucine compared to the ovine subunit which contains threonine. The beta subunit has two substitutions in the first 11 residues and does not contain the N terminal serine that is found in ovine FSH. Amino acid sequencing did not detect any contaminating proteins. Possum FSH bound possum and bovine testicular receptors with similar affinities. It was also able to stimulate in vitro cAMP production by Chinese hamster ovary cells which express recombinant FSH receptors. In the receptor assays and the bioassay possum FSH has about 21% of the potency of ovine FSH (USDA-oFSH-19-SIAFP-RP2). An RIA was developed for possum FSH using 125I-possum FSH and an antiserum raised against human FSH. The RIA has a sensitivity of 0.3 ng/ml, a 50% displacement of 2.7 ng/ml, and a cross reactivity of 0.05% against possum LH. Plasma FSH levels in male possums (10.4 +/- 2.4 ng/ml, n = 4) were higher (P < 0.05) than levels in females (1.0 +/- 0.1 ng/ml, n = 4). Five days after gonadectomizing these possums the plasma FSH levels increased (P < 0.05) to 27.1 +/- 0.2 ng/ml in the males and to 6.6 +/- 2.0 ng/ml in the females. In summary, we have purified and partially characterized possum FSH. We have also set up an RIA for the hormone and shown that males have higher levels than females and that plasma FSH increases after gonadectomy.

Applied home care research

Posits that Canadian home care services compete with hospitals and other community and public health agencies for scarce financial resources but as yet regional authorities are not responsible for paying physicians. Investigates all the various facets of home care services and concludes that by using joint ventures, there may be the possibility of making informed decisions for the Canadian healthcare system.

Independent depressive mechanisms of GABA and (+/-)-8-hydroxy-dipropylaminotetralin hydrobromide on young rat spinal axons

We compared the effect of GABA and the serotonin receptor agonist (+/-)-8-hydroxy-dipropylaminotetralin hydrobromide (8-OH-DPAT) on compound action potential amplitudes, latency, and conduction velocity in the spinal cord isolated from young (eight to 13-day-old) Long-Evans hooded rats. Supramaximally activated conducting action potentials and extracellular K+ activity were recorded with microelectrodes from the cuneatus-gracilis fasciculi and corticospinal tract. In the cuneatus-gracilis fasciculi, 8-OH-DPAT (10(-4) M) significantly reduced response amplitudes by 26.1 +/- 10.3% (mean +/- S.D., P < 0.0001, paired t-test, n = 27) and increased latencies by 20.3 +/- 7.9% (P < 0.0001). GABA (10(-4) M) reduced/amplitudes by 31.7 +/- 15.0% (P < 0.0001, n = 28) and increased latencies by 6.1 +/- 5.4% (P < 0.0001). However, neither GABA nor 8-OH-DPAT significantly altered conduction velocities, suggesting that the latency shifts are due to changes in activation time and not conduction velocity. In cortical spinal tract, 8-OH-DPAT (10(-4) M) depressed response amplitudes by 18.9 +/- 9.6% (P < 0.05, n = 5), increased latencies by 23.3 +/- 7.2% (P < 0.0001), but reduced conduction velocities by 19.9 +/- 10.2%. GABA (10(-4) M) reduced amplitudes by 16.4 +/- 7.5% (P < 0.01, n = 5), increased latencies by 5.3 +/- 2.3% (P < 0.05), and did not change conduction velocities. Bicuculline or picrotoxin blocked the GABA effects but did not affect the 8-OH-DPAT effects on both tracts. The potassium channel blocker tetraethylammonium did not alter the 8-OH-DPAT effects. The Na+/K(+)-ATPase inhibitor ouabain (10(-6) M) markedly enhanced the depressive GABA effects from 27.9 +/- 12.0% to 49.4 +/- 24.5% (P < 0.01, n = 9), but had no effect on 8-OH-DPAT-mediated effects. These results suggest that GABA and serotonin agonists depress axonal excitability through different and independent mechanisms.

Devolution of hip and knee replacement surgery?

The objectives of this study were to assess trends in referral patterns for joint replacements (JRs) in Ontario between the fiscal year 1988/89 and the fiscal year 1993/94; to assess the redistribution of financial resources if services were provided to residents in the region where they reside; and to estimate the financial implications of the devolution of primary JRs from tertiary-care hospitals to community hospitals. Despite rapid growth in the provision of JRs, there was no significant change in their regional distribution. Community hospitals have increased their share of JRs at the expense of teaching hospitals. For hospitals located in Central east Ontario, the cost of providing JRs to nonresidents increased from $ 5.9 million in 1988/89 to $8.3 million in 1993/94. Devolution of primary JRs requires a minimum reallocation sum of $25.1 million, with potential cost savings of $4.3 million. Many obstacles limit the devolution and local provision of health care services, including modifications to referral patterns and the availability of provider expertise, especially when a substantial redistribution of resources is required. Better clinical data to evaluate outcomes and better patient-specific costing data are required. Devolution of services should be addressed in the context of appropriate institutional compensation for medical education.

Brush cytology for the diagnosis of rectal carcinoma

The use of brush cytology as an aid in the preoperative diagnosis of rectal cancer was prospectively assessed at 328 examinations in 289 consecutive patients with rectal lesions suspicious of carcinoma. Forty-five patients were reported as having benign polyps. There was 97 per cent agreement between conventional biopsy and cytology brushings for this group. Some 249 patients underwent a subsequent resection allowing comparison with formal histology. Forceps biopsy produced a true-positive diagnosis of cancer in 218 patients (89.7 per cent) and cytology in 222 (91 per cent). The sensitivity for forceps biopsy and cytology was 81 and 83 per cent respectively, with a combined sensitivity of 98 per cent. It is concluded that the addition of cytology to forceps biopsy increases the diagnostic yield in a single examination, and may be a complementary method of establishing the diagnosis of rectal lesions.

A new route of transmission for Escherichia coli: infection from dry fermented salami

OBJECTIVES

This study evaluated the production of dry fermented salami associated with an outbreak of Escherichia coli O157.H7 infection in Washington State and California.

METHODS

Facility inspections, review of plant monitoring data, food handler interviews, and microbiological testing of salami products were conducted.

RESULTS

Production methods complied with federal requirements and industry-developed good manufacturing practices. No evidence suggested that postprocessing contamination occurred. Calculations suggested that the infectious dose was smaller than 50 E. coli O157:H7 bacteria.

CONCLUSIONS

Dry fermented salami can serve as a vehicle of transmission for O157:H7 strains. Our investigation and prior laboratory studies suggest that E. coli O157:H7 can survive currently accepted processing methods.