Spatial and temporal patterns of lin-12 expression during C. elegans hermaphrodite development.

The lin-12 gene encodes a receptor that mediates certain cell-cell interactions during Caenorhabditis elegans development. We have examined the expression of a lin-12::lacZ reporter gene in individual cells during the development of C. elegans hermaphrodites. lin-12::lacZ is expressed in a discrete spatial and temporal pattern during development and teh lin-12::lacZ reporter gene will provide a useful marker for other studies, particularly of somatic gonadal and vulval development. In general, the cells that express lin-12:: lacZ correspond to cells whose fates are known to be altered in lin-12 mutants implying that restriction of lin-12 expression may be an important regulatory mechanism; the exceptions to this statement may reveal the cellular defects that underlie aspects of the lin-12 phenotype that have not been previously explained. For decisions that are not naturally variable, lin-12::lacZ expression does not appear to change before or upon commitment to a cell fate implying that in these cases postranscriptional regulation of lin-12 activity may control cell fate specification.

Nuclear receptors have distinct affinities for coactivators: characterization by fluorescence resonance energy transfer.

UNLABELLED: Ligand-dependent interactions between nuclear receptors and members of a family of nuclear receptor coactivators are associated with transcriptional activation. Here we used fluorescence resonance energy transfer (FRET) as an approach for detecting and quantitating such interactions. Using the ligand binding domain (LBD) of peroxisome proliferator-activated receptor (PPARgamma) as a model, known agonists (thiazolidinediones and delta12, 14-PGJ2) induced a specific interaction resulting in FRET between the fluorescently labeled LBD and fluorescently labeled coactivators [CREB-binding protein (CBP) or steroid receptor coactivator-1 (SRC-1)]. Specific energy transfer was dose dependent; individual ligands displayed distinct potency and maximal FRET profiles that were identical when results obtained using CBP vs. SRC-1 were compared. In addition, half-maximally effective agonist concentrations (EC59s) correlated well with reported results using cell-based assays. A site-directed AF2 mutant of PPARgamma (E471A) that abrogated ligand-stimulated transcription in transfected cells also failed to induce ligand-mediated FRET between PPARgamma LBD and CBP or SRC-1. Using estrogen receptor (ERalpha) as an alternative system, known agonists induced an interaction between ERalpha LBD and SRC-1, whereas ER antagonists disrupted agonist-induced interaction of ERalpha with SRC-1. In the presence of saturating agonist concentrations, unlabeled CBP or SRC-1 was used to compete with fluorescently labeled coactivators with saturation kinetics. Relative affinities for the individual receptor-coactivator pairs were determined as follows: PPARgamma-CBP = ERalpha-SRC-1 > PPARgamma-SRC-1 >> ERalpha-CBP. CONCLUSIONS: 1) FRET-based coactivator association is a novel approach for characterizing nuclear receptor agonists or antagonists; individual ligands display potencies that are predictive of in vivo effects and distinct profiles of maximal activity that are suggestive of alternative receptor conformations. 2) PPARgamma interacts with both CBP and SRC-1; transcriptional activation and coactivator association are AF2 dependent. 3) Nuclear receptor LBDs have distinct affinities for individual coactivators; thus, PPARgamma has a greater apparent affinity for CBP than for SRC-1, whereas ERalpha interacts preferentially with SRC-1 but very weakly with CBP.

Intracranial pressure reserve testing. Initial clinical observations.

Sequential subdural injections of fluid through an intracranial pressure (ICP) monitoring cup catheter have been employed to measure "ICP reserve" in a series of 136 determinations in 30 patients over a total of 155 days of recordings. This dynamic method of quantitating the brain's ability to adapt to increased intracranial volume tests the brain's compensatory mechanisms over a five-minute time span. The test, incorporating several safety features, has been found to be reliable, safe, and well tolerated. A series of observations have been made using this test in patients with subdural drains and in response to fluid, mannitol, and dexamethasone therapy. Deteriorating ICP reserve gave early warning of the need for reoperation for postoperative hematoma, massive brain swelling, or cystic reaccumulation. Intracranial pressure reserve testing also quantitated the evolution of postoperative brain edema. Changes in ICP reserve could be detected as much as 48 hours before changes in baseline ICP and as much as 72 hours before clinical deterioration was evident.

Intracranial pressure reserve testing. A study in experimental animals.

Quantitating cerebral "elastance" or "ICP reserve" has added considerably to the value of continuous monitoring of intracranial pressure (ICP). Intracranial pressure reserve is a measure of the capacity of the brain's natural compensatory mechanisms for countering increases in ICP secondary to increases in intracranial volume. Intracranial pressure reserve testing was studied in dogs with known volumes of extracerebral intracranial mass, both in normal and in edematous brains and at various ICPs. Ten thousand measurements were made with five different methods of measuring ICP reserve. Testing when multiple increments of subdural saline infusion were used over a five-minute period to quantitate ICP reactivity to volumetric stress seemed most reliable and most adaptable to clinical application. Methods of measuring cerebral "elastance" using only a single subdural infusion proved to be variable and difficult to read.

Distinct effects of the antiestrogen Faslodex on the stability of estrogen receptors-alpha and -beta in the breast cancer cell line MCF-7.

The effects of estrogen receptor (ER) ligands on the stability and transcriptional activity of ERbeta in the breast cancer cell lines MCF-7 and HeLa were examined. We found that ERbeta was degraded in the presence of 17beta-estradiol. Tamoxifen and Faslodex (ICI 182,780) prevented ERbeta receptor destabilization. In contrast to ERalpha, ERbeta degradation was not abolished by inhibitors of the proteasome-mediated protein degradation pathway. Furthermore, single point mutations in helix 12 of the receptor dramatically affected the stability and subsequent transcriptional activation of ERbeta.

Inherent dangers of simultaneous application of microfibrillar collagen hemostat and blood-saving devices.

Microfibrillar collagen hemostat is a topically applicable hemostatic agent that has been introduced relatively recently. Because of the possibility that this substance may pass through different blood-collecting circuits and cause organ damage if reintroduced into the patient's circulation, we performed a series of in vitro and in vivo experiments. The results of these experiments suggest that such a passage may indeed occur and could cause organ damage, either by direct or by induced embolization that cannot be completely prevented even with the application of commercially used filters. We therefore recommend that the substance should not be used if the shed blood is intended to be collected and returned into the patient's circulation.

Percutaneous radiofrequency upper thoracic sympathectomy.

Between June 1979 and May 1994, I performed 148 unilateral or bilateral sympathectomies on 247 limbs in 110 patients using a percutaneous radiofrequency technique, usually on an outpatient surgery basis. Patient ages ranged from 10 to 81 years, with 45 male and 65 female patients. Four patients had unsuccessfully undergone prior open surgical sympathectomy. Patients suffered from hyperhidrosis, vascular occlusion, Raynaud's disease or other chronic vasculopathies, painful causalgia or reflex sympathetic dystrophy, or Prinzmetal's angina. The sympathectomy technique has evolved over this 15-year period and is currently in its third phase. Changes in the procedure were based on anatomic and clinical/radiographic correlations and careful patient follow-up. Current modifications have reduced the frequency of both early and late failures. The present technique (Phase III) relies on neuroleptanalgesia with superficial local anesthesia only and does not require general anesthesia, intubation, or lung collapse. Two 18-gauge radiofrequency TIC needle electrodes (Radionics, Burlington, MA) are used. A series of three lesions is rostrocaudally made at each of the ganglion sites selected in an attempt to destroy the entire fusiform ganglion. Lesion sites are targeted by C-arm fluoroscopy and electrical stimulation, which produces a threshold of sensory awareness of > 1.0 V. Lesion effectiveness is monitored by bilateral finger plethysmography and hand skin temperature measurement. With the Phase III technique, the sympathetic activity in 96% of operated limbs after 2 years and in 91% of operated limbs after 3 years continues to be completely or largely interrupted. By comparison, I achieved similar success in 83 and 72% operated limbs with the Phase I technique and in 77 and 71% with the Phase II technique. Symptomatic pneumothorax, in six patients, has been the only serious complication. When necessary, a subsequent operation can easily be performed and is effective.

The intracranial pressure-monitoring cup catheter: technical note.

The author describes a simple catheter designed for use in the measurement of intracranial pressure, especially during the initial stage following craniotomy. The device has been studied in experimental animals, and has been used in 40 neurosurgical patients for periods up to 15 days.

Percutaneous radiofrequency upper thoracic sympathectomy: a new technique.

The author describes a new technique for performing unilateral or bilateral upper thoracic sympathectomy safely, effectively, and more easily than by any of the surgical methods now in use. The technique described is one of percutaneous radiofrequency sympathectomy, which is usually done on a day surgery or outpatient surgery basis. The technique has been effective and well tolerated in a small group of patients.

Results of surgical lysis of lumbar adhesive arachnoiditis.

From a series of 681 patients with lumbar disc disease treated between 1966 and 1978, 17 patients required surgical lysis of lumbar adhesive arachnoiditis, 8 having initially been operated upon by another surgeon. All patients had severe pain as a predominant feature, with pain being bilateral in 9 patients. Pain was the only major symptom in 3; the other 14 exhibited varying combinations of progressive neurological dysfunction. Three patients developed late symptoms after trauma, 8 to 21 years after back surgery. At operation, multisegmental arachnoiditis was found in 5 patients and anular or subtotal adhesions were found in 12. Complete lysis could not be obtained in 4 patients. Fourteen patients were treated with steroids at the time of operation. Follow-up after lysis was less than 1 year for 5 patients but averaged 4.8 years for the remaining 12. During the 1st year after operation, 76% experienced improvement in pain (35%, good to excellent), 71% experienced improvement in neurological status. Follow-up after at least 1 year revealed 50% still enjoying pain relief (25%, good to excellent) and 45% experiencing neurological improvement. Pain relief persisted in 4 of 5 patients followed 5 years or more. The etiological role of myelograpy and lumbar disc surgery in arachnoiditis has probably been over-rated. Arachnoiditis may be symptomatic or asymptomatic and may mask other, treatable lumbar lesions. More frequent intradural exploration for discrepancies between operative and myelographic findings might reveal, and benefit, more cases of spontaneous arachnoiditis mimicking lumbar disc disease.

Furosemide and mannitol in the treatment of acute experimental intracranial hypertension.

Intracranial hypertension was induced in dogs and a small number of baboons by the inflation of epidural balloons. The resulting increased intracranial pressure (ICP) was treated with standard clinical doses of furosemide (0.7 mg/kg), "mini" doses of mannitol (0.75 g/kg), or both agents in combination. Mannitol consistently and rapidly reduced ICP in all animals. When results were averaged, furosemide used alone caused a slow reduction in ICP, but the results were variable in individual animals--with ICP actually increased in some. When furosemide and mannitol were given together, the ICP fell rapidly and remained low for considerably longer than after either agent alone.

T2 and T3 sympathetic ganglia in the adult human: a cadaver and clinical-radiographic study and its clinical application.

The technique of percutaneous radiofrequency (RF) upper thoracic sympathectomy mandates an exact knowledge of the anatomical location of the sympathetic ganglia. Because conflicting descriptions are given in anatomy texts, we examined the T2 and T3 sympathetic ganglia in 48 sympathetic chains in adult cadavers to measure the exact location of the ganglia. Measurements were made relative to their distances (a) dorsal to the ventral surface of the vertebral body and (b) rostral or caudal to the midpoint of the vertebral body. Median locations of T2 and T3 ganglia were 17 to 20 mm dorsal to the ventral surface of the vertebral body and 2 mm rostral to the T1-T2 and T2-T3 vertebral bodies. The sympathetic chains lay lateral to and between the heads of the ribs at these levels. A clinical-radiographic correlation study of the sympatholytic effectiveness of various needle electrode placement sites during sympathectomy confirmed these findings. These data have been used to modify the technique of percutaneous RF sympathectomy.

Synergistic effect between intraneoplastic methotrexate and radiation on experimental intracerebral rat gliosarcoma.

Methotrexate (MTX) alone has a limited effect against malignant brain tumors, but we previously demonstrated a beneficial synergism between MTX and radiation therapy (XRT) against RT-9 gliosarcoma. Because the beneficial effects of that study were limited by systemic toxicity and poor brain penetration of MTX, we have continued our studies using direct intracerebral MTX therapy. Male CD-Fisher rats with intracerebrally implanted RT-9 gliosarcoma and indwelling brain tumor catheters were treated with intracerebral injections of MTX, whole-brain XRT, or a combination of both. MTX was given either as one of two "high-dose" treatments, on the basis of whole-body doses, or two "low-doses," on the basis of average brain weight. MTX alone at lower doses and XRT alone each prolonged survival moderately. High-dose MTX was highly toxic, but low-dose MTX was well tolerated. Combined MTX and XRT caused a significant prolongation of survival in all animals that survived treatment long enough to die from tumor growth.

Synergistic effect of methotrexate and radiation on gliosarcoma in tissue culture and in rats.

In vitro and in vivo studies were performed on rat gliosarcoma cells (RT-9) to investigate the synergistic effect of methotrexate and radiation against malignant brain tumors. For in vitro study, RT-9 cells were cultured on microtiter plates and treated with methotrexate, radiation, or both. For in vivo study, the cells were implanted into the cerebrums of CD-Fischer rats, and intraperitoneal methotrexate, whole brain radiation, or both were given. Although synergistic suppression of cell growth with combined therapy was observed in the in vitro study, synergism was less clearly demonstrated in tumor-bearing rats because of systemic toxicity of the therapy.

Bilateral anterior cingulotomy for chronic noncancer pain.

OBJECTIVE: To document the value of bilateral anterior cingulotomy for patients with intractable chronic noncancer pain. METHODS: Twenty-three patients who underwent 28 cingulotomies between 1979 and 1996 for chronic refractory pain were sent questionnaires regarding their subjective response to the surgery and its impact on their pain. Questions dealt with pre- and postoperative pain, ability to resume work or usual activity, medications, family and social interactions, and overall benefit of cingulotomy. Results were compared with long-term (average, 8 yr) clinical follow-up. In 13 patients, pain was predominantly caused by lumbar adhesive arachnoiditis or "failed back." The remainder had venous occlusive disease, ischemic bilateral leg pain, phantom leg pain, postoperative neck pain, or atypical facial pain. RESULTS: Eighteen patients returned questionnaires; two patients died of unrelated causes. Seventy-two percent of patients reported improvement in their pain, 55% were no longer taking narcotics, 67% noted improvement in their family life, and 72% noted improvement in their social interactions. Fifty-six percent of patients reported that the cingulotomy was beneficial, and 28% returned to their usual activities or work. Thirty-nine percent of patients developed transient or well-controlled seizures. Five patients required a second cingulotomy, and one patient did well despite developing brain abscesses. Patient assessments corresponded closely with clinical assessments. CONCLUSION: Bilateral anterior cingulotomy is safe for patients with refractory chronic pain. Seizures reported in this series were well controlled with medication. More than half of all respondents thought they had a positive outcome and that cingulotomy was beneficial to them. There were no deaths related to the procedure.

Erroneous measurement of intracranial pressure caused by simultaneous ventricular drainage: a hydrodynamic model study.

Intracranial pressure (ICP) is often measured from intraventricular catheters, a technique that allows therapeutic drainage of ventricular cerebrospinal fluid (CSF) as an aid in controlling ICP and circumventing obstruction. Drainage of CSF simultaneously with ongoing ICP measurement has been advocated as safe and efficient, and devices are commercially available to permit this practice; however, this concept has been seriously challenged, based on clinical observations. The inaccuracy induced by simultaneous CSF drainage and ICP monitoring is quantitated in this report in a mechanical brain model using a standard ventricular catheter. The following conclusions have been confirmed: 1) rapid CSF drainage induces a severe artifactual reduction in measured ICP, more extreme at higher pressures; 2) calibrated slower rates of CSF drainage produce a severe, although less immediate, reduction in measured ICP; 3) severe artifact appears even in the presence of continuous CSF outflow, so a system that measures ICP only in the presence of CSF flow does not prevent artifact; 4) with simultaneous CSF drainage, measured ICP is determined more by the outflow pressure setting than by actual brain pressure; 5) Since ICP elevation of 25 to 30 mm Hg blocks CSF production, even slow fluid drainage at high pressures should ultimately lead to ventricular collapse and severe artifact.

Lumbosacral meningismus complicating subdural injection of "blood patch": case report.

The published literature suggests that the technique of epidural "blood patch" injection is both safe and effective for the treatment and prevention of headache after spinal puncture. However, a case is reported in which the complications following a "blood patch" outweighed the disability and discomfort produced by the headache itself. The etiology is believed to have been inadvertent injection of blood into the subarachnoid space.

Trigeminal nerve peripheral branch phenol/glycerol injections for tic douloureux.

OBJECT: Trigeminal neuralgia or tic douloureux is a disease affecting older individuals, and thus, office-based "minimally invasive" therapy is inherently attractive. The author sought to determine whether injection of peripheral trigeminal branches with neurolytic solutions offers a simple, less invasive therapy, with low risk for patients with one- or two-division trigeminal neuralgia that is unresponsive to pharmacotherapy. METHODS: This retrospective study focused on a review of case charts from 18 patients treated for tic douloureux. Sixty injections of 10% phenol in glycerol were given to the 18 patients, six of whom had undergone other neurosurgical procedures. The median patient age was 74 years, ranging from 36 to 94 years. There were nine women and nine men. Forty-six injections were administered into the infraorbital nerve in its canal in the midface, 11 percutaneous injections were administered into the mandibular nerve just proximal to the mandibular canal in the ramus of the jaw, and three injections were administered into supraorbital nerves. Eighty-seven percent of injections brought marked or total relief initially. Of those injections that provided initial relief, 37% still provided relief after 1 year and 30% after 2 years, with relief lasting for a median of 9 months after each injection. Most patients whose pain recurred after months of relief requested a repeated procedure, rather than undergo a ganglion nerve block procedure or open surgery. There were no serious complications or dysesthetic pain. Facial sensory loss generally recovered within 6 months and was well tolerated. CONCLUSIONS: Office-based injection of trigeminal branches is a useful technique for neurosurgeons who treat trigeminal neuralgia. It is easily repeated and can provide immediate pain relief of intermediate duration.

Sensory ganglionectomy: theory, technical aspects, and clinical experience.

OBJECT: Sensory ganglionectomy offers theoretical advantages over rhizotomy but remains controversial because reported success rates vary widely. The authors sought to add to the available data on this subject and to review technical aspects of the surgery. METHODS: This retrospective chart review included 19 patients, in whom 22 operations were performed and 35 sensory ganglia were resected between May 1995 and May 1999. The eight women and 11 men ranged in age from 27 to 75 years (median age 40 years, average age 42.3 years). All patients had undergone extensive therapy and a mean of 2.4 previous operations (median three, range zero-eight operations) for their pain, all without long-term pain relief. Duration of symptoms varied, from 1 month (for the cancer patient) to 15 years (mean 5.9, median 4 years). Preoperatively, all patients underwent diagnostic selective nerve root blocks, which temporarily relieved their targeted pain. The duration of follow up averaged 22 months (median 13, range 1.5 [to death of the cancer patient]-58 months). Before undergoing the first ganglionectomy, nearly all patients rated their targeted pain as 8 to 10 (average 9.6, median 10) on an analog (0-10) pain scale. At 6 months all patients rated their ganglionectomy-specific pain as an average of 4.5 (median 4, range 0-8), and pain reduction of 50% or more was achieved in 74%. At 1 year or more the 13 patients available for study rated their pain as an average of 4.3 (median 4.5, range 0-9). There were no severe complications, residual pain was never worse than presurgical pain, and no patient experienced significant or lasting new motor deficits. CONCLUSIONS: Dorsal root ganglionectomy has a useful role in the treatment of a variety of refractory pain states, especially those involving radicular pain.

Gelfoam paste in experimental laminectomy and cranial trephination: hemostasis and bone healing.

The hemostatic properties and effect on osteogenesis of gelatin foam paste and bone wax were compared on surgical bone lesions in experimental animals. Thirty rabbits each received four trephine craniotomies and four lumbar laminectomies. Alternate bone incisions in each animal were treated with either gelatin foam paste or bone wax. Blood loss was measured by absorbing the blood into dry surgical cottonoids weighed before and after use. Bone healing sites of three rabbits were examined histologically to assess the effect of each agent on osteogenesis. The trephination sites of eight rabbits were subjected to fracture force testing at 6 weeks postoperatively to compare the effect ot the two agents on bone healing. No significant difference was found between gelatin foam paste and bone wax in either effectiveness of hemostasis or effect on osteogenesis.