The unresolved role of the neurologist in providing dietary advice to people with multiple sclerosis

BACKGROUND

People with MS often make dietary changes after diagnosis with the aim of slowing disease progression. Although people with MS commonly use the internet for information on diet and MS, neurologists are their preferred source of information. However, little is known about what dietary advice is provided by neurologists.

OBJECTIVES

To explore the perceptions of neurologists about diet and MS, and to identify the type of dietary advice they provide to their patients with MS.

METHODS

In this exploratory qualitative study, 11 semi-structured interviews were conducted with neurologists in Western Australia. Audio files were transcribed verbatim, and transcripts were thematically analysed using a general inductive approach.

RESULTS

Four themes emerged: 1) juggling the evidence on the role of diet in MS; 2) acknowledging the risks and benefits of specific diets; 3) distancing from the diet 'gurus'; and 4) the unresolved role of the neurologist in providing dietary advice.

CONCLUSION

Neurologists could meet their patients' expectations by providing evidence-based dietary advice, such as promoting the benefits of diets that adhere to national dietary guidelines, and being prepared to explain potential risks of restrictive diets. Information about healthy eating needs to be targeted to people with MS.

The effectiveness of emotional wellness programs on mental health outcomes for adults with multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

People with multiple sclerosis (MS) have a greater prevalence of depression and anxiety than the general population. Emotional wellness programs (any psychological or psychosocial interventions that focus on awareness, acceptance, managing, or challenging thoughts and feelings) could be important for people with MS. However, there have been no reviews on the effectiveness of emotional wellness programs for people with MS. The objective of this review was to determine the effectiveness of emotional wellness programs on mental health outcomes for adults with MS.

INCLUSION CRITERIA

Randomised controlled trials (RCTs) and quasi-experimental trials evaluating emotional wellness programs for adults with any form of MS were included. Mental health outcomes included were depression, anxiety, quality of life, and stress. The comparator groups were waitlist controls, usual care, or another intervention.

METHODS

This review was registered with PROSPERO (registration number CRD42019131082) and conducted in accordance with PRISMA guidelines. CINAHL, Cochrane, MEDLINE, PsycInfo, Web of Science, ProQuest Dissertations and Theses, Cochrane register of Controlled Trials, and Google Scholar were searched for English- language publications. Titles and abstracts were initially screened, followed by a screen of full text articles. Studies were critically appraised for methodological quality using the JBI standardised critical appraisal checklists. Data were extracted on intervention details, study outcome measures, behaviour change techniques, and results. Random effects meta-analyses were performed for outcomes assessed in at least five studies, with results reported as the standardised mean difference (SMD).

RESULTS

This review comprised 25 RCTs and four quasi-experimental studies (n participants=2323); 21 were included in meta-analyses. Meta-analyses produced statistically significant results favouring the interventions (SMD (95% CI) for depression -0.55 (-0.87, -0.24); anxiety -0.42 (-0.70, -0.14); quality of life 0.28 (0.14, 0.43); and stress -1.00 (-1.58, -0.43)). The most commonly used behaviour change techniques were behaviour practice/rehearsal, social comparison, and social support.

CONCLUSIONS

This review provides evidence to support the effectiveness of emotional wellness programs for improving mental health outcomes in adults with MS. However, these findings should be interpreted with caution given the high degree of heterogeneity between the studies, and potential for biases in analysis due to missing data and/or incomplete reporting.

Obesity, dieting, and multiple sclerosis

BACKGROUND

Obesity is common in the United States and is associated with a higher risk of relapse and comorbidities, and increased disease progression, in people with MS.

METHODS

We examined the prevalence of overweight and obesity in the MS Sunshine Study, a matched case-control study of multiple sclerosis in Southern California (470 cases, 519 controls). We reported the proportion of participants who adopted a specific diet for nutrition or weight loss purposes, and identified independent predictors of dieting.

RESULTS

In the total population, 32% and 37% were overweight and obese, respectively. Case participants were no more likely to adopt a specific diet for nutrition or weight loss purposes than control participants (10% and 11%, respectively). Being obese, younger, female or non-Hispanic were independently associated with dieting.

CONCLUSION

Despite the evidence that obesity can worsen MS prognosis, and the high prevalence of overweight/obesity, case participants were no more likely to adopt a specific diet than control participants. Improved nutrition education may help people with MS make healthy dietary changes for nutrition or weight loss purposes.

Bundled Payments for Care Improvement: Boom or Bust?

BACKGROUND

As early implementors of the Centers for Medicare and Medicaid Services (CMS) Bundled Payments for Care Improvement (BPCI) initiative, our private practice sought to compare our readmission rates, post-acute care utilization, and length of stay for the first year under BPCI compared to baseline data.

METHODS

We used CMS data to compare total expenditures of all diagnosis-related groups (DRGs). Medicare patients who underwent orthopedic surgery between 2009 and 2012 were defined as non-BPCI (n = 8415) and were compared to Medicare BPCI patients (n = 4757) who had surgery in 2015. Ninety-day post-acute events including inpatient rehabilitation facility or subacute nursing facility admission, home health (HH), and readmissions were analyzed.

RESULTS

The median expenditure for non-BPCI patients was $22,193 compared to $19,476 for BPCI patients (P < .001). Median post-acute care spend was $6861 for non-BPCI and $5360 for BPCI patients (P < .001). Compared to non-BPCI patients, BPCI patients had a lower rate of subacute nursing facility admissions (non-BPCI 43% vs 37% BPCI; P < .001), inpatient rehabilitation facility admissions (non-BPCI 3% vs 4% BPCI; P = .005), HH (non-BPCI 79% vs 73% BPCI; P < .001), and readmissions (non-BPCI 12% vs 10% BPCI; P = .02). Changes in length of stay for post-acute care were only significant for HH with BPCI patients using a median 12 days and non-BPCI using 24 days.

CONCLUSION

The objective of BPCI was to improve healthcare value. Through substantial efforts both financially and utilization of human resources to contain costs with clinical practice guidelines, patient navigators, and a BPCI management team, the expenditures for CMS were significantly lower for BPCI patients.

Stem geometry changes initial femoral fixation stability of a revised press-fit hip prosthesis: A finite element study

BACKGROUND

Stable femoral fixation during uncemented total hip arthroplasty is critical to allow for subsequent osseointegration of the prosthesis. Varying stem designs provide surgeons with multiple options to gain femoral fixation.

OBJECTIVE

The purpose of this study was to compare the initial fixation stability of cylindrical and tapered stem implants using two different underreaming techniques (press-fit conditions) for revision total hip arthroplasty (THA).

METHODS

A finite element femur model was created from three-dimensional computed tomography images simulating a trabecular bone defect commonly observed in revision THA. Two 18-mm generic femoral hip implants were modeled using the same geometry, differing only in that one had a cylindrical stem and the other had a 2 degree tapered stem. Surgery was simulated using a 0.05-mm and 0.01-mm press-fit and tested with a physiologically relevant loading protocol.

RESULTS

Mean contact pressure was influenced more by the surgical technique than by the stem geometry. The 0.05-mm press-fit condition resulted in the highest contact pressures for both the cylindrical (27.35 MPa) and tapered (20.99 MPa) stems. Changing the press-fit to 0.01-mm greatly decreased the contact pressure by 79.8% and 78.5% for the cylindrical (5.53 MPa) and tapered (4.52 MPa) models, respectively. The cylindrical stem geometry consistently showed less relative micromotion at all the cross-sections sampled as compared to the tapered stem regardless of press-fit condition.

CONCLUSIONS

This finite element analysis study demonstrates that tapered stem results in lower average contact pressure and greater micromotion at the implant-bone interface than a cylindrical stem geometry. More studies are needed to establish how these different stem geometries perform in such non-ideal conditions encountered in revision THA cases where less bone stock is available.

Circulating zonulin levels in newly diagnosed Chinese type 2 diabetes patients

AIMS

Studies suggest that type 2 diabetes mellitus is associated with increased gut permeability. Human zonulin is the only physiological mediator discovered to date that is known to regulate gut permeability reversibly by disassembling intestinal tight junctions. However, the relationship between zonulin and type 2 diabetes remains to be defined, and no Chinese population-based data were reported. The aim of this study was to investigate the association between serum zonulin levels and type 2 diabetes in a Chinese Han population.

METHODS

143 newly diagnosed type 2 diabetes patients, 124 patients with impaired glucose tolerance and 121 subjects with normal glucose tolerance were enrolled in this study. Serum zonulin was measured by ELISA.

RESULTS

Patients with type 2 diabetes had higher serum zonulin levels than impaired or normal glucose tolerant subjects. Serum zonulin correlated with body mass index, waist-to-hip ratio, triglyceride, total cholesterol, HDL-C, fasting plasma glucose, 2h plasma glucose, HbA1c, tumor necrosis factor α, interleukin 6, HOMA-IR and QUICK index using correlation analysis (p < 0.05 for all). Multivariate stepwise regression analysis showed that zonulin levels were independently associated with insulin resistance (β = 0.024, p = 0.005). In logistic regression analysis, zonulin levels were an independent predictor of type 2 diabetes (OR = 1.080, p = 0.037).

CONCLUSIONS

Serum zonulin levels are significantly elevated in newly diagnosed Chinese Type 2 diabetes patients, and are associated with dyslipidemia, inflammation and insulin resistance, indicating a potential role of zonulin in the pathophysiology of type 2 diabetes in Chinese.

Structural integrity after rotator cuff repair does not correlate with patient function and pain: a meta-analysis

BACKGROUND

The correlation between the structural integrity of rotator cuff repair and the clinical outcome for the patient remains controversial. The purpose of this study was to assess the relationship between patient function and structural integrity of the rotator cuff after repair.

METHODS

A systematic review and a meta-analysis were conducted for Level-I and Level-II studies showing outcome measures after rotator cuff repair and an imaging assessment of the structural integrity of the repair. Data extracted included patient demographics, tear size, repair type, clinical outcome measures, and repair integrity. Statistical analysis was performed to compare outcomes in patients on the basis of the structural integrity of repair at the time of the latest follow-up.

RESULTS

Fourteen studies met inclusion criteria and were included in the latest analysis. Of the 861 patients who underwent rotator cuff repair with a minimum of a one-year follow-up, 674 patients (78.3%) had intact repairs at the time of latest follow-up. There was no difference in tear size between patients with intact repairs and those with retears (p = 0.866). The University of California Los Angeles shoulder score, the Constant score, and the American Shoulder and Elbow Surgeons score increased and the visual analog scale score decreased in patients regardless of the structural integrity of the repair. Patients with intact repairs had higher Constant scores by 8.93 points (p < 0.0001) and higher University of California Los Angeles shoulder scores by 2.95 points (p = 0.0004). Postoperative American Shoulder and Elbow Surgeons scores were no different in patients with intact repairs or retears (p = 0.15). Postoperative visual analog scale scores were 0.93 points lower in patients with intact repairs (p = 0.01). Patients with intact repairs had increased strength in forward elevation by 2.40 kilograms (5.29 pounds) (p < 0.00001) and had a trend toward increased strength in shoulder external rotation (p = 0.06). Although these results are significant, the differences are not clinically important on the basis of the validation of these outcome measures.

CONCLUSIONS

The results of this study suggest that there is not a clinically important difference in validated functional outcome scores or pain for patients who have undergone rotator cuff repair regardless of the structural integrity of the repair. Patients with intact repairs do have significantly greater strength than those with retears.

Wound healing in total joint replacement

Satisfactory primary wound healing following total joint replacement is essential. Wound healing problems can have devastating consequences for patients. Assessment of their healing capacity is useful in predicting complications. Local factors that influence wound healing include multiple previous incisions, extensive scarring, lymphoedema, and poor vascular perfusion. Systemic factors include diabetes mellitus, inflammatory arthropathy, renal or liver disease, immune compromise, corticosteroid therapy, smoking, and poor nutrition. Modifications in the surgical technique are necessary in selected cases to minimise potential wound complications. Prompt and systematic intervention is necessary to address any wound healing problems to reduce the risks of infection and other potential complications.

Apixaban and rivaroxaban decrease deep venous thrombosis but not other complications after total hip and total knee arthroplasty

Apixaban and rivaroxaban are oral direct factor Xa (FXa) inhibitors used for VTE prevention after total hip (THA) and total knee arthroplasty (TKA). A meta-analysis of level I studies comparing rivaroxaban 10 mg daily or apixaban 2.5 mg twice daily to enoxaparin for the prevention of VTE after THA or TKA was performed analyzing efficacy and safety outcomes. Seven studies met the inclusion criteria including 24,385 patients. Oral FXa inhibitors were superior to enoxaparin in preventing DVT (p<0.00001). There was no difference in the rate of PE, death, major bleeding, blood transfusion requirement, reoperation for bleeding or postoperative wound infections. Oral FXa inhibitors are superior to enoxaparin in preventing DVT after THA and TKA. There is no difference in the rate of PE, death, or postoperative wound complications.

Impact of tunnels and tenodesis screws on clavicle fracture: a biomechanical study of varying coracoclavicular ligament reconstruction techniques

PURPOSE

The purpose of this study was to compare the load to fracture of distal clavicles with no tunnels, one tunnel, or 2 tunnels and to evaluate the effect of inserting tenodesis screws in the tunnels on load to fracture of the distal clavicle.

METHODS

Fifty right sawbone clavicles were obtained and divided into 5 groups (n = 10): group 1, normal clavicle; group 2, one tunnel, no tenodesis screw; group 3, 2 tunnels, no tenodesis screws; group 4, one tunnel with tenodesis screw; and group 5, 2 tunnels with 2 tenodesis screws. Tunnels were created using a 5-mm-diameter reamer, and 5.5 × 10 mm polyethyl ethyl ketone tenodesis screws were used. A 4-point bending load was applied to the distal clavicles. Load to failure was noted for each specimen.

RESULTS

Load to failure in clavicles without tunnels was significantly higher (1,157.18 ± 147.10 N) than in all other groups (P < .0005). No statistical differences were noted between groups 2, 3, 4, and 5. Load to failure was not statistically different in clavicles with one versus 2 tunnels. In addition, the use of tenodesis screws in the tunnels did not affect the load required to fracture.

CONCLUSIONS

The use of tunnels in the clavicle for coracoclavicular (CC) ligament reconstruction significantly reduces the load required to fracture the distal clavicle. The addition of tenodesis screws does not appear to significantly increase the strength of the clavicle in this construct.

CLINICAL RELEVANCE

CC ligament reconstruction techniques commonly use tunnels in the distal clavicle, which may render the clavicle more susceptible to fracture. This study helps quantify the effect of these tunnels on the strength of the distal clavicle.

Beyond the peak of the anterior glenoid rim: A cadaveric study

PURPOSE

The purpose of this study was to quantify the width of bone beyond the peak of the anterior glenoid rim and to determine if this anatomic region of the glenoid significantly affects measurement of the anteroposterior glenoid diameter.

MATERIALS AND METHODS

19 cadaveric scapulae were examined and the width of bone beyond the peak of the anterior glenoid rim was measured. The percent width of this region relative to the anteroposterior diameter of the glenoid was evaluated. Male and female specimens were compared. Measurements of the anteroposterior diameter of the glenoid, both including and excluding this region, were compared.

RESULTS

The mean width of bone beyond the peak of the anterior glenoid rim was 3.2 ± 0.7 mm, corresponding to 10.5% of the anteroposterior glenoid diameter. This anatomic region is of similar relative size in males and females (11% vs 10% of the glenoid diameter). Measurement of the anteroposterior diameter of the glenoid is significantly different depending on whether this region is included or not (P = 0.0064).

CONCLUSIONS

There exists a portion of the anterior glenoid that is beyond the peak of the anterior rim, and is not part of the concave articular surface. The width of this anatomic area comprises a significant percent of the anteroposterior glenoid diameter, and should be understood when quantifying and describing anterior glenoid bone loss in cases of glenohumeral instability.

CLINICAL RELEVANCE

Understanding of anterior glenoid anatomy is important in the evaluation of glenohumeral instability. The portion of glenoid bone beyond the anterior rim peak is likely important for its soft tissue attachments, but its contribution to bony stability may be misunderstood.

Area-based determination of bone loss using the glenoid arc angle

In patients with anterior glenohumeral instability, the most commonly observed osseous defect involves the anterior portion of the inferior glenoid. The amount of glenoid bone loss guides surgical treatment, with progressively larger defects not being amenable to arthroscopic soft-tissue procedures. Currently, there is no universally accepted method of quantifying glenoid bone loss. Two-dimensional area-based methods and 1-dimensional methods of measuring bone loss have both been described but cannot be used interchangeably. The surface area of a glenoid bony defect is a more comprehensive descriptor of its magnitude than the 1-dimensional width of the defect. Calculating surface area can be challenging. We describe a method of quantifying glenoid bone loss using a glenoid arc angle that corresponds to the surface area of the defect. The arc angle is easily measured by use of commonly used imaging software tools and is independent of the size of the glenoid or defect orientation. This method may prove valuable in preoperative planning for patients with anterior glenohumeral instability.

Anterior shoulder instability: a review of pathoanatomy, diagnosis and treatment

The glenohumeral joint is inherently predisposed to instability by its bony architecture. The incidence of traumatic shoulder instability is 1.7% in the general population. Associated injuries to the capsulolabral structures of the glenohumeral joint have been described and may play a role in predicting recurrent instability. Advanced imaging, computed tomography or MRI may be necessary to adequately evaluate for associated glenohumeral pathology. Treatment algorithms have traditionally included a period of non-operative management in all patients, however young athletic patients may often benefit from early operative treatment. Various open and arthroscopic surgical options exist to address anterior glenohumeral instability. Bony injuries including bony Bankart lesions and Hills Sachs lesion have been implicated in failed surgical management using techniques that address only the soft tissues. An individualized treatment approach, based upon the patient's injury pattern and expectations, will likely lead to the most successful outcome.

Does an enhanced surface finish improve acetabular fixation in revision total hip arthroplasty?

High-porosity "cancellous metal" coatings have been introduced to increase the fixation and biologic incorporation of acetabular cups. The strength of initial fixation provided by a cancellous metal cups vs conventional alternatives in the deficient revision acetabulum was investigated. Cancellous, plasma-sprayed, and beaded cups (n = 9) were implanted under controlled conditions into a validated model of the revision acetabulum. The greatest differences were seen in resistance to catastrophic (spin-out) failure that, for the cancellous shell, averaged 1076 ± 265 N, which was 25% greater than the plasma-sprayed implant (859 ± 214 N, P = .04) and 218% greater than the beaded implant (338 ± 123 N, P < .01). The cancellous coating also provided greater resistance to ultimate failure. These results suggest that these new cancellous metal coatings may represent a promising alternative for fixation in revision total hip arthroplasty.

Vesicoacetabular fistula in a chronically infected total hip arthroplasty

Fistula formation between the bladder and acetabulum related to total hip arthroplasty (THA) is rare, and few cases have been documented. Common features of the reported cases include a defect in the medial wall of the acetabulum, a chronically infected THA, a history of bladder injury, vesicocutaneous fistulas, and a history of pelvis radiation exposure. We report the case of a vesicoacetabular fistula discovered during antibiotic spacer placement in a woman with a chronically infected THA. The patient received bilateral ureteral stents extending from the renal pelvis to the urethra. Three months later, the patient was free of infection and was able to undergo reimplantation arthroplasty.

Management of posttraumatic extensive bone loss and osteomyelitis using a customized articulating knee spacer

The combination of infection and extensive bone loss presents a challenging reconstructive situation for surgeons performing total knee arthroplasty (TKA). We describe the case of a patient that suffered a grade III open fracture of the tibial plateau and developed a recurrent infection which resulted in loss of the proximal 15 cm of the tibia. Our solution was interim use of custom-made articulating, antibiotic-impregnated spacers followed by a structural tibial allograft and hinged TKA. At 2-year follow-up the patient is infection-free and is able to ambulate without the use of support.

Calcific leiomyoma. A unique case report

Leiomyomas are benign soft tissue tumors originating in smooth muscle. They present clinically as a soft tissue mass causing a well localized, paroxysmal pain. Treatment of choice for such lesions is total excision. Recurrence or malignant transformation of these tumors is rare. Calcific leiomyomas, as diagnosed in this study, have seldom been reported in the foot. When treating lesions involving atopic calcification, it is important to maintain a high level of understanding of the various etiologies, both metabolic and nonmetabolic, which may lead to calcium deposition in the soft tissues.

Repair of distal tendo Achillis rupture with the use of the Mitek Anchor System

Surgical repair of an acute, distal, tendo Achillis rupture in a 59-year-old diabetic male is described in which the Mitek Anchor System was used. The injury described is a distal tear of the insertion of the tendon into the calcaneus without avulsion fracture of the calcaneus. Sixteen months of postoperative follow-up care, including casting for equinus deformity, progressive weightbearing, range of motion exercises, and physical therapy, have been free of complications. The authors include a brief overview of historical and current reparative techniques for comparison. The authors conclude that the use of the Mitek Anchor System affords the surgeon a simple and effective method for the repair of acute, distal, tendo Achillis rupture when other methods cannot be used because of the location of the rupture.

Activation of substantia nigra pars reticulata neurons: role in the initiation and behavioral expression of kindled seizures

Numerous studies have implicated the substantia nigra pars reticulata (SNR) in the initiation and behavioral expression of kindled seizures. In immobilized, amygdala-kindled animals, SNR neurons have been shown to enter an intense burst-firing pattern during afterdischarge (AD). Taken together these findings raised the possibility that the SNR facilitates the expression of kindled seizures by directly propagating seizure activity into target structures. In this study we examined the relationship between activation of SNR neurons and the electrical (EEG) and behavioral (clonic motor) expression of kindled seizures using both immobilized and unrestrained animals. The principal findings were that: (1) in both immobilized and unrestrained animals the SNR neurons of kindled, but not control, animals were recruited into a burst-firing pattern during AD; (2) the onset of burst-firing was delayed until after the onset of AD; and (3) the onset of burst-firing was not correlated with the onset of rhythmic motor seizure activity. These findings support the idea that the development of kindling is associated with recruitment of SNR neurons into a seizure propagating network. However, these data suggest that activation of SNR neurons is not necessary for the expression of clonic motor activity and does not lower seizure threshold.

Twenty-four-hour post-seizure inhibition during limbic kindling requires seizure generalization

Male Long-Evans rats were kindled by stimulation of the pyriform cortex using an afterdischarge (AD) threshold procedure that triggered one AD every 24 h. AD threshold dropped rapidly as long as the seizures remained localized, reaching an asymptote of 30% of its initial value by the 6th AD. In contrast, AD threshold rose progressively across the first six generalized seizures (i.e. ADs accompanied by forelimb clonus). This elevation in threshold was dependent upon the daily elicitation of a generalized seizure, and the threshold returned to its previous low value after 4 seizure-free days. This indicates that post-seizure inhibition in the pyriform cortex is a transient response produced by generalized seizures and is not related to the relatively permanent changes that underlie kindling.

A word of caution in acute pain management

Within acute pain management, as within any rapidly expanding field of therapeutic endeavor, novel treatment modalities may on occasion overreach their scientific foundations. In general, a cautionary theme is expressed regarding the utilization of various therapies, lest their overzealous clinical implementation jeopardizes the advancement of this highly promising field. With regard to demand-mode opioid therapeutics in particular, several areas in need of corroborative or elucidative research have been delineated. The subject of dosing for acute pain conditions with opiates via the epidural route versus intravenous opioid administration is discussed from the perspectives of practicality and risk/benefit assignments. The advisability and means of using demand-mode techniques in order to resolve the central issue of inherent benefits of opioid administration via one route or another is also presented.

Conservative management of Tumarkin's otolithic crisis

Tumarkin's otolithic crisis (TOC), characterized by a sudden drop attack without accompanying loss of consciousness, vertigo or autonomic signs, is a rare phenomenon thought to be of peripheral origin and associated with late-stage Meniere's disease. The purpose of this paper is to describe the clinical course of TOC in our series; to discuss the relationship between TOC and the onset and symptomatology of pre-existent Meniere's disease, and to determine the management of patients with TOC.

Some cardiovascular effects of the insect repellent N,N-diethyl-m-toluamide (DEET)

Initial toxicological safety evaluations of the insect repellent N,N-diethyl-m-toluamide (DEET) indicated a potential hypotensive effect. The current study was initiated in order to pursue this aspect of DEET toxicity and to elucidate potential mechanisms for this response. Sublethal intraperitoneal injections of DEET in anesthetized rats were found to decrease mean blood pressure and heart rate in a dose-related fashion. Doses ranged from 56 to 225 mg/kg. Dogs treated with 225 mg/kg of DEET exhibited a similar hypotension and bradycardia. Cardiac output was also significantly reduced but stroke volume and total peripheral resistance were not altered. Lead II ECG changes included small increases in P-R and Q-T intervals. In a series of pharmacological studies in rats, DEET was found to decrease the hypotension and bradycardia associated with acetylcholine injection; epinephrine, norepinephrine, and histamine responses were not altered. Atropine pretreatment reduced but did not eliminate the hypotensive effects of DEET.

Anticonvulsant and antiepileptogenic actions of MK-801 in the kindling and electroshock models

The actions of MK-801, a noncompetitive antagonist at the N-methyl-d-aspartate subtype of excitatory amino acid receptor, were investigated on the development of kindling and on seizures in the electroshock and kindling models. The drug MK-801 potently and effectively suppressed the tonic hindlimb extension component of electroshock-induced seizures; it also suppressed both the electrophysiological and behavioral manifestations of the development of kindling. In contrast to its effects on electroshock-induced seizures and the development of kindling, MK-801 only partly reduced the duration of seizures in fully kindled animals and did not elevate the threshold for afterdischarge despite the use of a large dose, associated with profound untoward behavioral effects. Together with previous findings, these results support the idea that noncompetitive blockade of NMDA receptors markedly inhibits the development of kindling. The diminished effectiveness of MK-801 against kindled seizures suggests that MK-801 will not be a clinically-useful anticonvulsant against complex partial seizures.

Continuous intrathecal opioid analgesia: tolerance and cross-tolerance of mu and delta spinal opioid receptors

The tolerance effects of continuous intrathecal infusions of opioids at mu and delta receptors were studied in rats. These effects were compared to those of chronic systemic morphine. A chronic intrathecal infusion of the relatively selective delta agonist, [D-Ala2, D-Leu5]enkephalin (DADLE), produced a larger degree of tolerance to DADLE than to the highly specific mu-activating morphiceptin analog [N-methyl-Phe3, D-Pro4]morphiceptin (PL017). The slope of the analgesic dose-response curve for the highly specific delta agonist, cyclic [D-Penicillamine2, D-Penicillamine5]enkephalin (DPDPE), was significantly different (flatter) from those of mu agonists or DADLE. High-dose infusion of PL017 induced a 61-fold parallel shift of the dose-response curve for PL017. This same treatment also induced a corresponding flattened, nonparallel change of the dose-response curve for DADLE. This altered curve for DADLE was very similar in slope to that of DPDPE. Pretreatment with the irreversible mu antagonist, beta-funaltrexamine, caused a parallel rightward shift of the dose-response curve for PL017 but did not affect DPDPE activity. beta-Funaltrexamine treatment induced a nonparallel rightward shift of the dose-response curve for DADLE with a change of slope similar to that of DPDPE. These findings demonstrate a mixed mu-delta analgesic activity for the compound DADLE, which is often referred to as a prototypic delta agonist. These interactions differ from prior reports of none or minimal mu-ligand interactions with DADLE. Despite the cross-reactivity of DADLE to mu receptors, DADLE remains a more effective analgesic than do mu agonists in states of mu receptor tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of olfactory bulb kindling on evoked potentials in the pyriform cortex

The potential evoked in the pyriform cortex by single-pulse stimulation of the olfactory bulb was examined before and after single and repeated elicitation of an epileptiform afterdischarge produced by stimulation of the olfactory bulb. A single afterdischarge (AD) produced a rapid (i.e. within 5 min) increase in the amplitude of an early surface-negative wave and duration of a later surface-positive wave. These effects persisted at least 48-72 h. Repeated elicitation of ADs resulted in kindling. A large increase in the amplitude of a later surface-negative wave (approximately 25 ms latency) occurred during kindling. This wave remained significantly elevated for at least 72 h after the last AD. Long-term potentiation of the early surface-negative wave was produced by kindling or two focal ADs. A short-term effect which was consistently observed following a focal or generalized AD was a prolongation of a late surface-positive wave. These effects are discussed in relation to long-term potentiation, postseizure inhibition, and kindling development.

Effect of cocaine and pentylenetetrazol on cortical kindling

The effect of drug-induced convulsions on subsequent cortical kindling was studied in male Long-Evans rats. Animals experienced three intravenous infusions of physiological saline at 3 day intervals, or three convulsions induced by the infusion of cocaine or pentylenetetrazol (PTZ). Beginning eight days after the last infusion, all animals were kindled by stimulation of the anterior neocortex (area 6). PTZ-induced convulsions facilitated the development of both the behavioral convulsion and the electrographic seizure during cortical kindling, while cocaine-induced convulsions facilitated only the development of the electrographic seizure. Comparison of these results with previous research indicates that convulsions induced by these two drugs have long-lasting effects on brain function which differ both in their anatomical distribution and in the nature of the effects produced. These drugs also differed in their acute effects at subconvulsant doses on the expression of cortically kindled seizures. Cocaine (and lidocaine, another local anesthetic) substantially elevated afterdischarge (AD) threshold and inhibited the focal component of the cortically kindled seizure. PTZ had no significant effect on either of these variables but significantly increased AD duration. In addition to these drug effects, a substantial inhibitory effect on seizure expression was observed, both during kindling and afterwards, when ADs were elicited daily but not when they were separated by 3 days or more. This finding suggests that the large number of ADs typically required for cortical kindling may be due in part to daily stimulation.

Monoaminergic and local anesthetic components of cocaine's effects on kindled seizure expression

Male Long-Evans rats were kindled via daily electrical stimulation of the left prepyriform cortex. The animals were then used in two experiments which examined the pharmacological basis of cocaine's effects on three mutually exclusive components of the kindled seizure, which were the following: (a) latency to clonus, (b) clonus duration, and (c) duration of AD outlasting clonus. The first experiment compared the effects produced by cocaine HCl (20 mg/kg, IP), lidocaine HCl (20 mg/kg, IP), and amphetamine sulfate (2.5 mg/kg, IP). The results indicated that both cocaine and lidocaine reduced the duration of kindled AD, latency to clonus, and duration of AD persisting beyond clonus, thus suggesting that these cocaine effects are mediated by local anesthetic mechanisms. Only cocaine reduced clonus duration, which suggests that this cocaine effect is not produced by a local anesthetic action. The second experiment examined the effects of cocaine following the administration of three dose levels of the monoamine antagonists haloperidol, prazosin, yohimbine, propranolol, or metergoline (selected for their ability to block dopamine, alpha-1-norepinephrine, alpha-2-norepinephrine, beta-norepinephrine, and serotonin receptors, respectively). The results of this experiment found no support for a monoaminergic contribution to cocaine's effect on clonus latency or AD after clonus. However, results for prazosin, which reduced clonus duration and exhibited an additive effect with cocaine on this variable, suggest that cocaine's norepinephrine action (especially on the alpha-norepinephrine systems) may modulate clonus duration.

Embolization and angioplasty to relieve malignant hypertension and azotemia in a renal transplant patient

The case of a 23-year-old patient with malignant hypertension following a renal transplant illustrates the successful treatment of the hypertension with embolization of the native kidneys. Azotemia followed and was successfully treated with percutaneous transluminal angioplasty of high-grade stenosis at the anastomotic site of the allograft. Malignant hypertension redeveloped with the recanalization of the embolized native kidneys. This was successfully treated with contrast ablation.

Percutaneous embolization to control intractable epistaxis

Recurrent epistaxis is a common manifestation of patients with a bleeding diathesis. Two patients with epistaxis secondary to a bleeding diathesis managed by local conservative techniques are reviewed. (A case of polycythemia vera and a case of liver failure secondary to hepatoma are reviewed.) Recently bilateral, percutaneous carotid angiography examination was performed on a patient with a bleeding diathesis and intractable epistaxis. At the time of the angiographic examination, embolization of both internal maxillary arteries with Gelfoam particles was accomplished and dramatic control of the epistaxis was achieved. In a patient with severe epistaxis secondary to a bleeding diathesis that is unresponsive to local measures, percutaneous Gelfoam embolization offers substantial advantages over surgical intervention.