Periacetabular bone metabolism following hip revision surgery. PET-based evaluation of allograft osteointegration

The treatment of loosened total hip replacement (THR) acetabular components may require the management of severe bone defects. Although being applied for decades, there is only limited scientific data about the osteointegration of cancellous bone allografts (CBA) and other void fillers. Monitoring of periprosthetic bone regeneration could possibly help to optimize this process thereby reducing late failure rates. The aim of this study was to show osteometabolic changes in periprosthetic CBA after THR revision with the use of sodium-[18F]-fluoride (NaF) and positron emission tomography (PET).

PATIENTS, METHODS

Twelve patients undergoing THR revision with the use of CBA were prospectively enrolled in the study. Nine patients completed all necessary examinations and were included in the evaluation. The temporal pattern of osteointegration was assessed via NaF-PET at one (PET1) and six weeks (PET2) after surgery. CBA, tantalum implants, supraacetabular regions ipsilateral and contralateral, and parasymphyseal pubic bones were delineated as volumes of interest (VOI) in postop CT scans, which were then merged with the PET data.

RESULTS

In comparison to the contralateral supraacetabular reference bone, a significant 1.5-fold increase of osteometabolic activity from PET1 to PET2 was seen in the CBA region. Also, the ipsilateral supraacetabular host bone showed a higher NaF-influx in week 6, compared to the first postoperative week. The supraacetabular site exhibited a significantly 1.8- to 2-fold higher influx and uptake than bone regions in non-operated sites. Tantalum implants had a low NaF influx at both time points investigated.

CONCLUSION

Using NaF-PET osteometabolic changes of CBA and implant-bone-interfaces can be monitored. Applying this method we demonstrated early periprosthetic temporal bone regeneration patterns in THR cup revision patients.

Expression pattern differences between osteoarthritic chondrocytes and mesenchymal stem cells during chondrogenic differentiation

OBJECTIVE

The use of mesenchymal stem cells (MSCs) for cartilage regeneration is hampered by lack of knowledge about the underlying molecular differences between chondrogenically stimulated chondrocytes and MSCs. The aim of this study was to evaluate differences in phenotype and gene expression between primary human chondrocytes and MSCs during chondrogenic differentiation in three-dimensional (3D) pellet culture (PC).

MATERIALS AND METHODS

Chondrocytes isolated from cartilage samples obtained during total knee alloarthroplastic procedure (N=8) and MSCs, purified from bone marrow aspirates of healthy donors (N=8), were cultivated in PC under chondrogenic conditions. Immunohistology and quantitative reverse transcribing PCR (RT-PCR) were performed for chondrogenic-specific markers (i.e., Sox9, Collagen II). Global gene expression of the so-cultivated chondrocytes and MSCs was assessed by a novel approach of microarray-based pathway analysis. Refinement of data was done by hypothesis-driven gene expression omnibus (GEO) dataset comparison. Validation was performed with separate samples in transforming growth factor (TGF)β+ or TGFβ- conditions by use of quantitative real-time RT-PCR.

RESULTS/CONCLUSIONS

Chondrogenic commitment of both cell types was observed. Interestingly, chondrocytes demonstrated an upregulated fatty acid/cholesterol metabolism which may give hints for future optimization of culture conditions. The novel microarray-based pathway analysis applied in this study seems suitable for the evaluation of whole-genome based array datasets in case when hypotheses can be backed with already existing GEO datasets. Future experiments should further explore the different metabolic behaviour of chondrocytes and MSC.

[Perspectives of clinical stem cell therapy in the treatment of musculoskeletal diseases in Germany]

AIM

The treatment of large bone defects remains a challenge for the orthopaedic surgeon. Regenerative therapies with the use of mesenchymal stem cells (MSC) may provide an alternative to autogenous bone transplantation, callus distraction or the use of allografts.

MATERIAL AND METHODS

On the occasion of an expert workshop of the German Society for Orthopaedic and Trauma Surgery, a literature search regarding studies with the use of MSC was performed to evaluate its potential for future clinical studies. Furthermore, the legislative requirements were examined.

RESULTS

Various in vitro and animal studies showed the benefit of MSC in bone regeneration. However, there are sparse data from clinical studies. Due to recent legislative changes there are several regulatory demands to meet if clinical studies are performed with MSC.

CONCLUSIONS

For further evaluation of the role of MSC in the treatment of bone defects there is a need for clinical trials. The current paper provides some assistance for the successful application for clinical trials with MSC. Planning and performance of these studies may require early consultation with the regulatory authorities and cooperation of research centres in order to obtain authorisation for the evaluation of MSC. Preclinical data have to be obtained according to good laboratory practice with equivalent protocols that will be used in the clinical trials. In the latter the implementation of the guidelines for good clinical practice are mandatory.

[Survey of the simultaneous management of clinical and research burdens in German University orthopaedic and trauma departments]

AIM

Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals.

METHOD

With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, priorities and personal resources. It was possible to answer the questions by e-mail; later an anonymous online version of the survey was set in action as well.

RESULTS

Completely answered forms were received from n = 105 physicians, of which 88 % were judged as active researchers. Over 50 % of the participants were satisfied with their clinical career and with their research results. 96 % of the survey participants felt sure that most of the research could only be managed during spare time. A majority of the participants supported the idea of receiving leave of absence from clinical duties for research in order to serialise the scientific and clinical careers. Interestingly, when focusing on priority settings, salary aspects were ranked as low as research interests, falling behind the wish for a more intensive surgical training and more leisure time.

CONCLUSIONS

Individual solutions seem to be necessary to achieve a scheduled efficiency of clinical and research careers. This includes structural developments (like a professionally headed lab) and the establishment of dynamic clinical structures. It seems possible that the clinical organisation of physicians in teams might offer solutions to cope with the demands of surgical training and clinical care on the one hand and research on the other hand.

The utility of thrombo-elastography in the monitoring of aspirin therapy

To assess the utility of the thrombo-elastogram in monitoring of aspirin therapy 25 healthy volunteers were selected and given low-dose aspirin therapy. Thrombo-elastography and platelet aggregometry were conducted at baseline and 1 week later. After 1 week of aspirin therapy, thrombo-elastogram data failed to demonstrate a significant change in the clotting profile. Platelet aggregometry identified significant changes in the clotting profile in response to stimulation with arachidonic acid, adrenaline and ADP. We conclude that thrombo-elastography may not have utility in monitoring of response to aspirin.

[Necrosis of the femoral head in late pregnancy. Necessity of early diagnosis]

Limping and groin pain can issue diagnostic problems during late pregnancy. Differential diagnosis of two idiopathic syndromes, transient osteoporosis and osteonecrosis of the femoral head, is made possible by MRI in the early stages. This case is reported to demonstrate the need to distinguish between those syndromes early so as to prevent further joint damage.

The Plant Lectin Wheat Germ Agglutinin Inhibits the Binding of Pemphigus Foliaceus Autoantibodies to Desmoglein 1 in a Majority of Patients and Prevents Pathomechanisms of Pemphigus Foliaceus In Vitro and In Vivo

Pemphigus foliaceus (PF) is a life-threatening autoimmune blistering skin disease caused by pathogenic IgG autoantibodies against desmoglein 1 (dg1), a desmosomal cadherin-type adhesion glycoprotein. Using lectins and glycosidases, we have shown that dg1 displays an N-glycosylation pattern of the complex triantennary type. We have found that lectins and glycosidases interfere with N-bound sugar residues on the amino-terminal ectodomain of dg1 and completely abolish, in vitro, the antigenicity of dg1 in most of the patients' sera. Moreover, in an ex vivo model using punch biopsies from normal human skin, we demonstrate that preincubation of the epidermis in wheat germ agglutinin (WGA) prevents PF autoantibody binding, acantholysis, and subcorneal blistering. In addition, we show that topical treatment with WGA inhibits PF autoantibody binding to keratinocytes in both newborn BALB/c mice and in organotypic human epidermis grafted onto the back of SCID mice. The epidermis of these pretreated animals displays a regular morphology, whereas control animals develop the immunopathologic phenotype of PF. These findings suggest that WGA may interfere with autoantibody binding to dg1, preventing experimental PF without affecting the adhesive function of dg1. Our observations may provide a new approach to the therapy of PF.

Rapid initiation of gabapentin: a randomized, controlled trial

OBJECTIVE

To compare the tolerability of two different dose-initiation regimens of gabapentin for the adjunctive treatment of partial seizures.

BACKGROUND

Patient compliance is a key feature of successful outpatient pharmacologic therapy for epilepsy, and one aspect of compliance is simplicity of initiation. By using a rapid titration rate, leading to a rapid therapeutic gabapentin dose, perhaps there could be an improvement with compliance.

METHODS

Male or female patients, at least 12 years old, with a recent history of partial seizures with or without secondary generalization, were randomized to receive gabapentin (following a blinded placebo period of an undisclosed number of days) as either a Slow initiation (300 mg day 1, 600 mg day 2, then 900 mg/day) or a Rapid initiation (900 mg/day immediately following the placebo lead-in).

RESULTS

Starting gabapentin therapy at an initial therapeutic dosage of 900 mg/day is well tolerated by patients with epilepsy and is as safe as initiating with a titration schedule over 3 days. Of the four most common adverse events (somnolence, dizziness, ataxia, fatigue), only one, dizziness, occurred more often in the nontitrated (Rapid initiation) group than in the titrated (Slow initiation) group.

CONCLUSION

Initiation of gabapentin at 900 mg/day is as well tolerated as is a 3-day titration, except for a higher incidence of dizziness.

Efficacy of gabapentin as adjunctive therapy in a large, multicenter study. The Steps Study Group

The objective of this study was to determine the efficacy of gabapentin as adjunctive therapy in doses required to achieve the most effective seizure control. There were 2016 patients with partial seizures requiring adjunctive therapy who received gabapentin at doses up to 3600 mg/day in this open-label, multicenter, 16-week study. Of the 1055 patients evaluable for efficacy, 573 received gabapentin < or =1800 mg/day and 482 received > 1800 mg/day as the highest dose received. For the overall efficacy evaluable population, the percentage of patients achieving at least a 50% reduction in seizure frequency was 76.0%; 46.4% of the patients were seizure free. Patients whose highest gabapentin dose did not require > 1800 mg/day had, at baseline, fewer seizures and were receiving fewer concomitant antiepileptic drugs (AEDs) at baseline than those patients requiring > 1800 mg/day. This suggests that patients requiring higher doses of gabapentin were more refractory to drug treatment at the start of the study. Gabapentin was well tolerated at all doses in this study. The results of the study demonstrate that gabapentin is effective as adjunctive therapy in patients with partial seizures whose seizures are inadequately controlled by traditional AEDs.

Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome

Gitelman's syndrome is an autosomal recessive disorder of salt wasting and hypokalemia caused by mutations in the thiazide-sensitive Na-Cl cotransporter. To investigate the pathogenesis of Gitelman's syndrome, eight disease mutations were introduced into the mouse thiazide-sensitive Na-Cl cotransporter and studied by functional expression in Xenopus oocytes. Sodium uptake into oocytes that expressed the wild-type clone was more than sevenfold greater than uptake into control oocytes. Uptake into oocytes that expressed the mutated transporters was not different from control. Hydrochlorothiazide reduced Na uptake by oocytes expressing the wild-type gene to control values but had no effect on oocytes expressing the mutant clones. Western blots of oocytes injected with the wild-type clone showed bands representing glycosylated (125 kDa) and unglycosylated (110 kDa) forms of the transport protein. Immunoblot of oocytes expressing the mutated clones showed only the unglycosylated protein, indicating that protein processing was disrupted. Immunocytochemistry with an antibody against the transport protein showed intense membrane staining of oocytes expressing the wild-type protein. Membrane staining was completely absent from oocytes expressing mNCC(R948X); instead, diffuse cytoplasmic staining was evident. In summary, the results show that several mutations that cause Gitelman's syndrome are nonfunctional because the mutant thiazide-sensitive Na-Cl cotransporter is not processed normally, probably activating the "quality control" mechanism of the endoplasmic reticulum.

Safety and tolerability of gabapentin as adjunctive therapy in a large, multicenter study

PURPOSE

To evaluate the tolerability and safety of gabapentin (GBP) as add-on therapy for seizure control.

METHODS

Conducted in an outpatient setting and reflecting usual practice, this study compared tolerability of GBP dosages < or = 1,800 versus >1,800 mg/day, when these doses were required to achieve the most effective seizure control. Two analyses of adverse events are presented: tolerability and safety. In the tolerability analysis, each patient served as his or her own control to compare the occurrence of adverse events at GBP < or =1,800 versus >1,800 mg/day. The safety analysis required patients to receive at least one dose of GBP and have a follow-up contact.

RESULTS

A total of 2,216 patients enrolled in this open-label, 16-week study and were evaluable for safety. Of these, 74.0% completed the 16-week study, and 281 met the tolerability criteria. Within these 281 patients, two mutually exclusive groups were compared (a) those reporting adverse events at only < or =1,800 mg/day (low dose); and (b) those reporting adverse events at only >1,800 mg/day (high dose). Three adverse events (asthenia, headache, and dizziness) were observed in a statistically significantly larger number of patients at only the low dose than in the group reporting these same adverse events at only the high dose, suggesting that patients who tolerated GBP at < or = 1,800 mg/day did not experience a significant increase in adverse events with dosages >1,800 mg/day. Overall, 10.6% of the 2,216 patients in the safety population prematurely withdrew because of adverse events, and 3.5% discontinued because of lack of efficacy. Safety and tolerability of GBP was rated as excellent or good for 78.5% of all patients.

CONCLUSIONS

Gabapentin doses >1,800 mg/day were as well tolerated as doses < or =1,800 mg/day and were not associated with more adverse events.

Brain adaptation to acute hyponatremia in young rats

Brain swelling after acute hyponatremia in prepubescent rats, in contrast to adults, has recently been associated with an increase in brain sodium and a high mortality that could be prevented by preadministration of testosterone. To reexamine the effect of acute hyponatremia in young brain, we measured brain water and solute content in prepubescent rats after induction of hyponatremia over 4 h with water and arginine vasopressin. An 18% decrease in plasma sodium was associated with a 13% increase in brain water and a decrease in brain sodium and glutamate contents. No animals died. To assess the effect of sex hormones on brain adaptation, prepubescent rats were pretreated with estrogen or testosterone before acute hyponatremia. Brain sodium and potassium contents were significantly reduced in comparison to normonatremia in testosterone-pretreated but not estrogen-pretreated animals. However, there was no difference between estrogen-pretreated and testosterone-pretreated groups in mortality or in brain contents of water, electrolytes, or major organic osmolytes. In conclusion, we found that brain adaptation to acute hyponatremia in prepubescent rats is similar to that observed in adults.

Gabapentin for the treatment of postherpetic neuralgia: a randomized controlled trial

CONTEXT

Postherpetic neuralgia (PHN) is a syndrome of often intractable neuropathic pain following herpes zoster (shingles) that eludes effective treatment in many patients.

OBJECTIVE

To determine the efficacy and safety of the anticonvulsant drug gabapentin in reducing PHN pain.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled, parallel design, 8-week trial conducted from August 1996 through July 1997.

SETTING

Sixteen US outpatient clinical centers.

PARTICIPANTS

A total of 229 subjects were randomized.

INTERVENTION

A 4-week titration period to a maximum dosage of 3600 mg/d of gabapentin or matching placebo. Treatment was maintained for another 4 weeks at the maximum tolerated dose. Concomitant tricyclic antidepressants and/or narcotics were continued if therapy was stabilized prior to study entry and remained constant throughout the study.

MAIN OUTCOME MEASURES

The primary efficacy measure was change in the average daily pain score based on an 11-point Likert scale (0, no pain; 10, worst possible pain) from baseline week to the final week of therapy. Secondary measures included average daily sleep scores, Short-Form McGill Pain Questionnaire (SF-MPQ), Subject Global Impression of Change and investigator-rated Clinical Global Impression of Change, Short Form-36 (SF-36) Quality of Life Questionnaire, and Profile of Mood States (POMS). Safety measures included the frequency and severity of adverse events.

RESULTS

One hundred thirteen patients received gabapentin, and 89 (78.8%) completed the study; 116 received placebo, and 95 (81.9%) completed the study. By intent-to-treat analysis, subjects receiving gabapentin had a statistically significant reduction in average daily pain score from 6.3 to 4.2 points compared with a change from 6.5 to 6.0 points in subjects randomized to receive placebo (P<.001). Secondary measures of pain as well as changes in pain and sleep interference showed improvement with gabapentin (P<.001). Many measures within the SF-36 and POMS also significantly favored gabapentin (P< or =.01). Somnolence, dizziness, ataxia, peripheral edema, and infection were all more frequent in the gabapentin group, but withdrawals were comparable in the 2 groups (15 [13.3%] in the gabapentin group vs 11 [9.5%] in the placebo group).

CONCLUSIONS

Gabapentin is effective in the treatment of pain and sleep interference associated with PHN. Mood and quality of life also improve with gabapentin therapy.

Is the attenuation of beta-adrenergic agonist efficacy during labor caused by elevated prostaglandin E levels?

OBJECTIVE

Our purpose was to investigate whether attenuation of beta-adrenergic agonist efficacy during labor is due to elevated prostaglandin E levels.

STUDY DESIGN

beta-Receptor function (response to beta-agonist or forskolin) was tested in mononuclear leukocytes collected from women at term before or during labor. beta-Receptor function was also tested in mononuclear leukocytes of nonlaboring patients after in vitro incubation with oxytocin (1 micromol/L), prostaglandin E2 (10 micromol/L), prostaglandin F2alpha (10 micromol/L), or buffer alone.

RESULTS

Mononuclear leukocytes from women in active labor exhibited a significant attenuation of beta-adrenergic receptor function as a result of reduced adenylyl cyclase activity. This effect could be induced in mononuclear leukocytes from nonlaboring women by preincubation with prostaglandin E but not oxytocin or prostaglandin F.

CONCLUSIONS

Prostaglandin E induces heterologous desensitization of the beta-adrenergic receptor system in mononuclear leukocytes, comparable to that seen during labor. We speculate that during labor the elevated levels of prostaglandin E may induce similar effects on the myometrium, thereby decreasing the efficacy of beta-agonists as tocolytics.

Can risk factor screening predict hepatitis C antibody reactivity?

The object of this study was to investigate the prevalence of Hepatitis C virus (HCV) by second-generation testing and to determine the effectiveness of risk factor-guided screening. We performed a prospective study of HCV exposure determined by second-generation enzyme-linked immunoadsorbent assay (ELISA) and confirmed by radioimmunoblot assay (RIBA). Risk factors (RF) were interpreted by univariate and multivariate analyses. Eight hundred eighty-six consecutive patients were tested for HCV over a 1-year period; 34 women tested positive for HCV and 32 were confirmed by RIBA (prevalence 3.6%). Forty-nine percent of women had at least one RF. Age, intravenous drug use, history of hepatitis strongly correlated with HCV (p <0.001). RF screening had a sensitivity of 81%. Twenty-one percent of women with HCV had no RF. The absence of any RF had a negative predictive value of 98.7%. RF screening is effective in identifying patients at low risk for HCV.

Adrenal steroids stimulate thiazide-sensitive NaCl transport by rat renal distal tubules

The current experiments were designed to test the hypothesis that adrenal steroids increase thiazide-sensitive Na and Cl transport by the mammalian renal distal convoluted tubule (DCT). Male Sprague-Dawley rats were adrenalectomized and received steroid hormones by osmotic pumps. Six groups of animals were studied as follows: group I, no hormones; group II, replacement levels of dexamethasone only; group III, replacement levels of aldosterone only; group IV, replacement levels of both hormones; group V; replacement levels of aldosterone and high levels of dexamethasone; and group VI, replacement levels of dexamethasone and high levels of aldosterone. Circulating levels of both hormones were found to be in the high physiological range when infused at the high rate. In vivo microperfusion of distal tubules was performed to determine rates of Na and Cl transport. Chlorothiazide was used to assess the magnitude of electroneutral Na-Cl cotransport. Both aldosterone and dexamethasone stimulated thiazide-sensitive Na and Cl transport by the distal tubule by more than fivefold. [3H]metolazone binding was measured to assess the number of thiazide-sensitive Na-Cl cotransporters in renal cortex. Each steroid also increased the number of [3H]metolazone binding sites in kidney cortex more than threefold. The results are consistent with the presence of both mineralocorticoid and glucocorticoid receptors in the mammalian DCT. Physiological changes in circulating levels of adrenal steroids may affect renal NaCl excretion in part by regulating the rate of electroneutral Na-Cl absorption by the DCT.

Event-related brain potentials and error-related processing: an analysis of incorrect responses to go and no-go stimuli

Recent research has suggested that there is a component of the event-related brain potential, the error-related negativity (ERN), that is associated with error detection and remedial actions such as error inhibition, immediate error correction, or error compensation. The present experiment used a go/no-go task to define more precisely the functional significance of this component. In this task, an ERN was observed for incorrect responses on go trials (errors of choice) and for responses on no-go trials (errors of action). Because errors of action cannot be corrected immediately by executing another response, these results indicate that the process manifested by the ERN is not dependent on immediate error correction. Other aspects of the data converge in suggesting that the ERN process is more closely related to error detection and that the connections between detection and remedial actions may depend on the task situation.

Expression of the thiazide-sensitive Na-Cl cotransporter in rat and human kidney

An electroneutral thiazide-sensitive Na-Cl cotransport pathway (TSC) has been localized functionally to the distal convoluted tubule (DCT), although the TSC has also been detected in the connecting tubule (CNT), the cortical collecting duct, and the medullary collecting tubule as well. The present experiments were designed to localize expression of message for the TSC in rat and human kidney. A riboprobe, generated from the mouse TSC, was used for in situ hybridization. Simultaneous immunocytochemistry, using antibodies to Tamm-Horsfall protein, band 3, and the Na+/Ca2+ exchanger, permitted delineation of specific nephron segments. In rat, message for the TSC was highly expressed in DCT cells but not elsewhere. The transition from thick ascending limb to DCT was abrupt, whereas the transition to CNT was gradual. In the more distal region of rat DCT (DCT-2), which contained few intercalated cells, both TSC message and Na+/Ca2+ exchanger immunoreactivity were present. Treatment of rats with furosemide for 5 days increased expression of TSC message within the DCT but did not induce its expression elsewhere. In humans, expression of TSC message was also highest in cells of the DCT. In humans, however, expression extended well into the CNT. These experiments indicate that the TSC is expressed predominantly by DCT cells in both rat and humans, although expression extends into the CNT cells in humans. They also show that the TSC and Na+/Ca2+ exchanger are coexpressed by a subpopulation of DCT cells near the junction with the CNT.

A new uterine manipulator for operative laparoscopic hysterectomy

A new, reusable uterine manipulator was developed to facilitate pelviscopic surgery and laparoscopic hysterectomy. The device is weighted to hold the uterus in an anteverted position and allow easy access to the cul-de-sac. It is spring loaded to create a tight seal for tubal insufflation. The instrument is calibrated in centimeters and has a sliding cervical plug that allows it to be inserted into the fundus to a depth of 15 cm for uterine manipulation during laparoscopic hysterectomy. The spring-loading mechanism holds the device firmly to the cervical tenaculum regardless of the depth of penetration, and rotates 180 degrees for use in the retroverted uterus.

Shifting students and faculty to a PBL curriculum: attitudes changed and lessons learned

BACKGROUND

The University of Toronto Faculty of Medicine is implementing a new undergraduate curriculum that emphasizes active, self-directed learning. The aims of this study were to (1) evaluate shifts in students' attitudes after initial direct experience with problem-based learning (PBL), (2) describe faculty experiences, and (3) develop guidelines for further implementation of PBL.

METHOD

Questionnaires were administered at the beginning of the first PBL session and at the close of the last session (five weeks later) to the 250 second-year students in 1992-93 and to their 15 faculty tutors. Quantitative data were analyzed using multivariate analysis of variance and univariate tests. Open-ended questions were categorized based on common patterns that emerged.

RESULTS

Of the 250 students, 196 (78%) responded to the pretest, and 207 (83%) responded to the posttest. There was a statistically significant shift in the students' perceptions from pretest to posttest in agreeing that PBL is more effective than traditional teaching methods (increasing from 38% to 52%). The students rated traditional methods as better for knowledge acquisition, whereas PBL methods were rated better for improving teamwork and doctor-patient relationships. At pretest, the most common themes concerned a perceived danger that PBL would result in knowledge gaps, reinforce the wrong information, and make inefficient use of valuable time. Perceived advantages of PBL included that it is more stimulating and enjoyable, and it teaches students how to learn rather than to memorize. At posttest, there was an increase in favorable comments by the students. Virtually all of the attitudes expressed by the students were shared by the faculty. In addition, at pretest the faculty were anxious about the perceived lack of structure in PBL.

CONCLUSION

Direct experience with PBL led to more favorable attitudes among the students and faculty. Recommendations are suggested for other schools and programs seeking to implement PBL curricula.

The relationship of the skin conductance and finger pulse amplitude components of the orienting response to season of birth in schizophrenia and depression

Schizophrenia is said to be associated with a modest excess of winter births. We examined relations of season of birth (SOB) to the skin conductance response (SCR) and finger pulse amplitude response (FPAR) components of the orienting response (OR) in 83 schizophrenic patients, 59 depressed patients, and 81 normal controls. SCR-OR nonresponding was more prevalent among depressed patients regardless of SOB, whereas only winter-born schizophrenics showed significantly more frequent electrodermal nonresponding than controls. However, this latter relation was not confirmed with log linear analysis. No other relations of SOB to SCR-OR or FPAR-OR nonresponding were significant. Our data do not support the view that nonresponding in the SCR or FPAR components of the OR is associated with winter birth either in schizophrenia or depression.

Differing patterns of electrodermal and finger pulse responsivity in schizophrenia and depression

Non-response of the autonomic orienting response (OR), as indexed jointly by deficient skin conductance (SCR) and finger pulse amplitude responding (FPAR), has been shown to occur with excessive frequency in the schizophrenic population. The present study is an attempt to replicate earlier evidence that SCR-OR and FPAR-OR, when measured in concert, could distinguish schizophrenic from depressed patients (Bernstein et al. 1988). This issue is critical of the question of diagnostic specificity of OR non-responding, since reduced SCR has been found repeatedly in depression as well as in schizophrenia. We examined SCR and FPAR concurrently in 69 schizophrenic, 45 depressed, and 67 normal subjects. SCR non-responding was more frequent in both schizophrenics and depressives than in normal controls, while only the schizophrenics displayed excessive FPAR non-responding. Moreover, among SCR non-responders, concordant OR non-responding--defined as non-responding indexed simultaneously in both the SCR and FPAR components--was most common in the schizophrenic sample. These findings support our previous conclusion that OR non-responding in depression, may have distinct peripheral origins. Our results also suggest that measuring multiple biochemically distinct components of the OR may be more sound methodologically than obtaining a single channel recording.

Introduction of laparoscopically assisted vaginal hysterectomy in a private teaching community hospital

STUDY OBJECTIVE

To compare laparoscopically assisted vaginal hysterectomy (LAVH) with traditional total abdominal hysterectomy (TAH) when the laparoscopic approach is introduced into a private hospital.

DESIGN

During 1 year, 49 LAVHs were performed and compared with 51 consecutive TAHs using retrospective chart review and statistical analysis.

SETTING

A private, university-affiliated, teaching hospital.

PATIENTS

All patients undergoing LAVH, and the first 51 TAHs performed during the study year.

MEASUREMENTS AND MAIN RESULTS

No major complications occurred in either group. Significant differences were observed in uterine weight (161 +/- 92 g vs 331 +/- 354 g), operating time (164 +/- 48 min vs 108 +/- 28 min), and hospital stay (2.93 +/- 1.21 days vs 4.00 +/- 1.54 days) for LAVH and TAH, respectively. Hospital charges for LAVH average $4074 more than for TAH, primarily due to the use of disposable laparoscopic equipment.

CONCLUSIONS

Laparoscopically assisted vaginal hysterectomy may be performed safely in a private community hospital with appropriate surgeon credentialing and training. Modifying techniques to minimize the use of disposable equipment would make the procedure more cost effective.

Prostaglandin E2 gel for cervical ripening and labour induction: a multicentre placebo-controlled trial

OBJECTIVE

To determine the effect of a single intracervical dose of prostaglandin E2 (PGE2) gel on cervical ripening and the need for subsequent labour induction with oxytocin.

DESIGN

Multicentre randomized, double-blind, placebo-controlled study.

SETTING

Tertiary care hospitals.

PATIENTS

A total of 397 women met the inclusion criteria: gestational age of at least 36 weeks, parity of 3 or less, a Bishop score of 4 or less, intact membranes, an indication for induction, no contraindication to vaginal delivery, no history of cesarean section or major uterine surgery, no hypersensitivity to prostaglandins, no previous attempt at cervical ripening or induction, no vaginal bleeding and no fetal abnormalities.

INTERVENTION

The experimental group (203 women) received a low dose (0.5 mg) of PGE2 in 2.5 mL of gel and the control group (194) 2.5 mL of a placebo gel intracervically. The observation period was 12 hours before further induction (with oxytocin) was attempted.

OUTCOME MEASURES

Ripening effect of gel, need for induction with oxytocin, rate of labour induction, time from gel administration to delivery.

RESULTS

Seventeen women could not be evaluated because induction was not attempted after the first 12 hours (in nine cases) or the induction attempt was delayed for 24 hours (in six); in the other two cases the gel was in place for only 2 1/2 and 4 hours respectively before cesarean section was required. The Bishop score 12 hours after the gel administration and the difference in the score from the time of admission to the end of the 12-hour observation period were significantly higher in the experimental group than in the control group (p less than 0.001). In all, 91 (46%) of the 196 patients in the experimental group went into labour within the 12-hour observation period, as compared with 21 (11%) of the 184 in the control group (p less than 0.001). When the women who required further induction were included the rate of successful induction was 85% (166 women) and 72% (132) respectively (p less than 0.004). The mean interval from the time of gel administration to delivery was smaller in the experimental group than in the control group (19.8 v. 24.1 hours respectively) (p less than 0.001).

CONCLUSIONS

A single, low dose of PGE2 gel administered intracervically is a safe and reliable method of dealing with indicated but potentially difficult inductions.

Antithrombin-III-Aktivitätsabfall im Plasma unter intravenöser kontinuierlicher Heparintherapie

30 Patienten im Alter von 20-67 Jahren mit einer phlebographisch gesicherten tiefen Bein-Bekken-Venenthrombose wurden 8 Tage lang intravenös kontinuierlich mit Heparin-Natrium von Hoffmann-La Roche bzw. Ratiopharm behandelt. Bei diesen Patienten wurde eine Vollantikoagulierung mit einer Verlängerung der partiellen Thromboplastinzeit >60 bis 90 s angestrebt. Die Heparindosis variierte zwischen 25000-60000 IE/ 24 Std. In beiden Behandlungsgruppen hatte das Körpergewicht der Patienten einen hochsignifikanten Einfluß auf die Heparindosis, bei der eine Verlängerung der partiellen Thromboplastinzeit >60 s erreicht wurde. Bei allen Patienten fiel unter der kontinuierlichen Heparintherapie das Antithrombin III (AT III) um durchschnittlich 3,3 IU/ml ab. Das Ausmaß des AT-III-Abfalls variierte individuell, korrelierte nicht mit der Heparindosis.

Poly(A), poly(A) binding protein and the regulation of mRNA stability

This review has focused on the possibility that interactions between mRNA sequences and the poly(A)-nucleoprotein complex play important roles in mRNA turnover. It is important to stress that additional genetic and biochemical tests are necessary to characterize how PABP interacts with mRNA in cells and to determine whether the poly(A) protection hypothesis is accurate. Moreover, there may be a significant number of mRNAs whose half-lives are independent of polyadenylation. For example, the stabilities of poly(A)-containing and deadenylated alpha 2u-globulin and interferon mRNAs are similar in microinjected oocytes. Thus, an important challenge in this field will be to analyse the complex and interactive factors that determine the half-lives of specific mRNAs.

The poly(A)-poly(A)-binding protein complex is a major determinant of mRNA stability in vitro

Using an in vitro mRNA decay system, we investigated how poly(A) and its associated poly(A)-binding protein (PABP) affect mRNA stability. Cell extracts used in the decay reactions were depleted of functional PABP either by adding excess poly(A) competitor or by passing the extracts over a poly(A)-Sepharose column. Polyadenylated mRNAs for beta-globin, chloramphenicol acetyltransferase, and simian virus 40 virion proteins were degraded 3 to 10 times faster in reactions lacking PABP than in those containing excess PABP. The addition of purified Saccharomyces cerevisiae or human cytoplasmic PABP to PABP-depleted reactions stabilized the polyadenylated mRNAs. In contrast, the decay rates of nonpolyadenylated mRNAs were unaffected by PABP, indicating that both the poly(A) and its binding protein were required for maintaining mRNA stability. A nonspecific single-stranded binding protein from Escherichia coli did not restore stability to polyadenylated mRNA, and the stabilizing effect of PABP was inhibited by anti-PABP antibody. The poly(A) tract was the first mRNA segment to be degraded in PABP-depleted reactions, confirming that the poly(A)-PABP complex was protecting the 3' region from nucleolytic attack. These results indicate that an important function of poly(A), in conjunction with its binding protein, is to protect polyadenylated mRNAs from indiscriminate destruction by cellular nucleases. A model is proposed to explain how the stability of an mRNA could be affected by the stability of its poly(A)-PABP complex.

Cervical ripening and labor induction with prostaglandin E2 gel: a placebo-controlled study

A randomized double-blind, placebo-controlled study was undertaken to evaluate the effect of a single intracervical application of prostaglandin E2 gel on the ripening of the cervix and on the subsequent induction of labor with oxytocin in patients with low Bishop scores (less than or equal to 4). Compared to controls receiving gel only, the group receiving prostaglandin E2 gel had significant increases in their cervical Bishop scores, shorter induction-to-delivery intervals, shorter time requiring use of oxytocin, and more successful labor induction without oxytocin. Systemic side effects were minimal and fetal outcomes were comparable, as were the routes of delivery.

Regulation of protein degradation in muscle by calcium. Evidence for enhanced nonlysosomal proteolysis associated with elevated cytosolic calcium

Calcium-dependent regulation of intracellular protein degradation was studied in isolated rat skeletal muscles incubated in vitro in the presence of a large variety of agents known to affect calcium movement and distribution. A23187, KC1, sucrose, and 8-(diethylamino)octyl-3,4, 5-trimethoxybenzoate hydrochloride increase proteolysis while tetracaine, verapamil, and low extracellular calcium caused significant decreases. Additionally, dantrolene decreases proteolysis in the presence of depolarizing levels of potassium, while it has no effect on degradation in normal media. The dose dependence of calcium ionophore A23187 on proteolysis and contracture tension are parallel. Furthermore, excess KC1 and hypertonic solutions increased protein degradation at doses reported to cause tension. Thus, the parallel increase in proteolysis and tension in response to various agents supports the hypothesis that protein degradation in muscle is regulated by calcium. To determine the responsible proteolytic systems involved in calcium-dependent degradation, the effect of different classes of protease inhibitors was tested. Addition of the inhibitors leupeptin and E-64-c blocked the A23187-induced increase in degradation. Since proteases sensitive to these agents are present in both the sarcoplasm and lysosomes, known lysosomotropic agents, methylamine and chloroquine, as well as 3-methyladenine, a specific autophagy inhibitor, were used in combination with A23187. These agents did not inhibit calcium ionophore-induced proteolysis, although these three agents selectively inhibited enhanced degradation seen in the absence of insulin, demonstrating an autophagic/lysosomal pathway in these muscles. Thus, our results suggest that nonlysosomal leupeptin- and E-64-c-sensitive proteases are responsible for calcium-dependent proteolysis in muscle.

Immunophenotype of human melanoma cells in different metastases

The pattern of melanoma-associated antigens (MAAs) expressed on the surface of melanoma cells in 23 metastases, 15 obtained from different patients and 8 from different metastases in two patients, was studied by immunoprecipitation and sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis using monoclonal and polyclonal melanoma antisera. Though there were differences in the MAAs expressed by each melanoma, there were marked similarities as well. No more than two melanomas had a similar pattern of MAAs. However, all melanomas expressed some MAAs, and most MAAs were commonly expressed by several melanomas. Two of the MAAs studied, with molecular weights of approximately 75,000 and 95,000 to 97,000, were particularly well represented, and at least one of these two antigens was expressed by all melanoma cells. These results suggest that complete absence of tumor-associated antigens on metastatic melanoma cells is a rare phenomenon. All melanoma lines we studied expressed at least one of a restricted number of antigens. Thus despite antigenic heterogeneity, sufficient similarity remains between different melanomas to permit specific immunotherapy to be targeted to a limited number of tumor antigens.

Attrition in maintenance therapy for recurrent depression. A preliminary report

All maintenance treatment programs are complicated by the issue of patient noncompliance. This report investigates factors contributing to noncompliance during a 2-year study designed to evaluate the efficacy of long-term antidepressant medication in patients with recurrent unipolar depression. Only 21 of 51 patients (49%) who entered maintenance treatment successfully completed this phase of the study. Fifteen patients (8 completers and 7 dropouts) were randomly selected for an interview which focused on their previous psychiatric treatment history and attitudes towards the maintenance treatment program. In addition, these patients also completed a comprehensive personality battery. Results indicate that, while both groups had similar attitudes about the treatment program, they differed significantly along personality and psychiatric treatment history variables. Dropouts scored higher than completers on a measure of hysterical personality style. They were also more likely to have received psychotherapy in previous treatment experiences and to rate it as beneficial, while completers consistently rated prior treatment, which did not include antidepressant medication, as being of no benefit whatsoever. In order to enhance patient compliance, it is important to obtain information early in treatment about patients' treatment histories and their expectations about effective treatment for depression.

Premature rupture of membranes: the role of C-reactive protein in the prediction of chorioamnionitis

A group of 52 patients with premature rupture of the membranes (PROM) before 34 weeks' gestation were evaluated prospectively and managed expectantly. Of 42 patients who were delivered of their infants, 26 (61.9%) had significant chorioamnionitis on histopathology, and 18 had positive microbial cultures at delivery. However, only seven patients (16.7%) developed clinical signs of chorioamnionitis. There were no maternal deaths or perinatal deaths attributable to sepsis. Only two infants (less than 5%) had positive blood cultures. All patients were assessed daily for the development of chorioamnionitis. Amniocenteses were not routinely performed. White blood cell counts, band neutrophil counts, and erythrocyte sedimentation rate determinations were found to be unreliable. C-reactive protein determinations were found most reliable with a high sensitivity and specificity. Elevated C-reactive protein levels correlated better with pathologic confirmation of chorioamnionitis than with the clinical febrile morbidity. Clinical implications for the management of PROM are discussed.

Short-term antibiotic prophylaxis in high-risk patients following cesarean section

A prospective, blinded, placebo-controlled study was performed to determine the minimum effective duration of short-term antibiotic prophylaxis following cesarean section. Cefoxitin was selected as the study drug, and 189 women at high risk for postoperative infectious morbidity were randomly assigned to three cohorts, each receiving intravenous infusions at cord clamping and at 4 and 8 hours postoperatively. The incidence of endometritis in the placebo group was 29.3% versus 9.4% in patients receiving one dose of cefoxitin (2 gm) at cord clamping and 5.0% in patients receiving three doses of cefoxitin (p less than 0.0001). Cefoxitin prophylaxis significantly reduced the incidence of endometritis in patients with postoperative anemia. There were no serious complications or drug reactions in the treated groups.

Comparative potency and pharmacology of isomers of leukotriene D4 on guinea-pig trachea: requirement for a 5(S)6(R) configuration

The relative contractile activity of C5 and C6 diastereomers of Leukotriene D4 (LTD4), as well as 11-trans stereoisomers were evaluated in guinea-pig tracheal smooth muscle. 5(S)6(R) LTD4 was 1000 times more potent than histamine as a contractile agent. While a change of the 11-ethylenic bond from cis to trans resulted in a four fold decrease in potency, a change in configuration of the 5-hydroxyl group and/or the 6-peptide adduct resulted in a decrease in potency of at least 2 to 3 orders of magnitude. The contractile activity of all LTD4 isomers was inhibited by FPL 55712, whereas indomethacin markedly enhanced the contractile activity of 5(S)6(R) LTD4, but appeared to have less of an effect on the other diastereomers. The results demonstrate the critical nature of configuration of the 5-hydroxyl and the 6-peptide adduct of eicosatetraenoic acid for maintenance of high affinity for receptors.

Risk factors associated with infection following cesarean section

A retrospective study by means of multivariant discriminant analysis was performed on 496 deliveries (250 vaginal and 246 cesarean sections) is identify risk factors which predispose to postoperative febrile morbidity, in particular, endometritis. The infection rates for endometritis by type of delivery were: vaginal, 3.6%; elective repeat cesarean section, 6.0%; nonurgent primary cesarean section, 22.2%; and emergency cesarean section, 38.4%. No patient-related risk factors were identified for elective repeat cesarean section, and bacterial isolates were most frequently Staphylococcus aureus. However, four statistically significant risk factors were associated with the occurrence of endometritis after primary cesarean section. In increasing order of significance, they were duration of labor, number of preoperative vaginal examinations, time membranes were ruptured prior to delivery, and postoperative anemia. Internal fetal monitoring was not a risk factor. The clinical relevance of these findings to the use of prophylactic antibiotics and other attempts aimed at decreasing postoperative morbidity is discussed.