Median nerve evoked responses and explicit memory during recovery from isoflurane/nitrous oxide anesthesia

PURPOSE

To evaluate median nerve somatosensory evoked responses during recovery from anesthesia in relation to clinical findings.

METHODS

Twenty-two gynecologic patients received isoflurane in nitrous oxide for anesthesia. Midlatency somatosensory evoked responses (N20, P25, N35, P45, N50) were recorded the day before surgery (AWAKE), during steady state anesthesia (STABLE), and every five minutes after discontinuation of anesthesia until the patients were able to name a shown object correctly (RECOVERY). Next day the patients were questioned with a structured interview about their explicit memory of the immediate recovery period and classified into groups: No-MEM (no memory) and MEM (memory). Multivariate analysis of variance compared electrophysiological parameters at the different time points and between the two memory groups.

RESULTS

During STABLE isoflurane/N2O anesthesia, all cortical amplitudes were reduced (P< or =0.003) and all latencies were prolonged compared with AWAKE (P<0.001). At RECOVERY the latencies N35, P45, N50 remained prolonged (P< or =0.001), while the amplitudes N20P25 and P45N50 were reduced in comparison to AWAKE (P< or =0.02). The latencies P45 (48+/-8 vs. 61+/-9 msec) and N50 (67+/-12 vs. 81+/-10 msec) were shorter in the patients of the group MEM (P< or =0.03) at RECOVERY.

CONCLUSION

The reversibility of anesthetic induced changes in amplitudes and latencies of median nerve somatosensory evoked responses reflected clinical awakening during emergence from isoflurane/nitrous oxide anesthesia. In the patients who had recall for the immediate recovery period, the reversibility of anesthetic induced changes of components P45 and N50 was faster than in patients without recall.

[The window in the falciform ligament. A rare case of hernia of the small intestine through the falciform ligament]

The most common causes for small-bowel obstructions with subsequent strangulation are intra-abdominal adhesions and external hernias. We report an unusual case of strangulated small-bowel hernia through a congenital window in the falciform ligament. The diagnosis and surgical treatment are discussed.

Midlatency median nerve evoked responses during recovery from propofol/sufentanil total intravenous anaesthesia

BACKGROUND

Median nerve somatosensory evoked responses (MnSSER) are frequently used to monitor the integrity of the somatosensory pathway during surgery. We investigated MnSSER components during the wakeup phase from anaesthesia with propofol/sufentanil, because detailed information is lacking about the reversibility of anaesthetic induced changes of MnSSER. The aim of the study was to document precisely the MnSSER waves in relation to the clinical awakening. The hypothesis was that anaesthetic induced MnSSER changes are reversed when the patient becomes responsive after anaesthesia.

METHODS

In 20 gynaecological patients anaesthesia was maintained with propofol 8 mg kg(-1) h(-1) supplemented by bolus injections of sufentanil. MnSSER were recorded at C4' (N20, P25, N35, P45, N50) following electrical median nerve stimulation on the day before surgery, after the end of surgery during anaesthesia and every 5 min during recovery, till the patients were responsive again and able to identify a shown object.

RESULTS

While the primary cortical MnSSER complex N20P25 regained baseline values, the cortical latencies > or =35 ms remained prolonged (P<0.001) and the amplitudes P45N50 were suppressed (P< or =0.013), when the patients were responsive after 26+/-7 min following anaesthesia. However, the amplitudes P25N35 exceeded their corresponding baseline value (P<0.01)

CONCLUSION

Persistent changes of MnSSER waves > or =35 ms reflect impaired signal processing along the somatosensory pathway following propofol/sufentanil anaesthesia when the patients are responsive again. Further studies combining MnSSER recording with distinct neuro-psychological tests are needed to define the clinical relevance of these findings.

Evaluation of magnetic resonance cholangiography in the management of bile duct stones

HYPOTHESIS

Magnetic resonance cholangiography (MRC) offers the potential for accurate, noninvasive detection of common bile duct stones (CBDSs) before cholecystectomy, and for a consequent reduction in the incidence of preoperative negative diagnoses associated with endoscopic retrograde cholangiography (ERC).

DESIGN

Prospective cohort study: MRC results were correlated with ERC (high-risk patients) or intraoperative cholangiography (moderate-risk patients).

SETTING

A university hospital providing primary, secondary, and tertiary care.

PATIENTS

Seventy patients with suspected CBDSs scheduled to undergo elective cholecystectomy between April 15, 1997, and September 30, 1998. Forty patients were considered at high risk and 30 at moderate risk for CBDSs, according to results of liver function tests and sonograms of the upper abdomen.

MAIN OUTCOME MEASURES

Confirmation or exclusion of CBDSs by MRC was assessed by a panel of radiologists who were unaware of the ERC results. Results of ERC and intraoperative cholangiography were analyzed by the investigating gastroenterologists or surgeon.

RESULTS

Results of MRC were positive for CBDSs in 21 (52%) of 40 high-risk patients, a finding confirmed by preoperative ERC in 19 (90%) of 21 patients. Results of MRC were positive for CBDSs in 6 (20%) of 30 moderate-risk patients, all of which were confirmed by intraoperative cholangiography. Finally, CBDSs were present in 19 (48%) of 40 high-risk patients and 6 (20%) of 30 moderate-risk patients (P = .02). Overall sensitivity and specificity of MRC were 100% and 95.6%, respectively; the positive and negative predictive values were 92.6% and 100%, respectively.

CONCLUSIONS

Magnetic resonance cholangiography is a reliable, noninvasive method for the detection or exclusion of CBDSs, and seems to reduce the frequency of negative diagnoses associated with ERC. Magnetic resonance cholangiography revealed no CBDSs in 19 (48%) of 40 patients at high risk for CBDSs. Thus, MRC-based diagnosis has the potential to reduce the number of invasive preoperative diagnostic procedures and their associated risks and overall health care costs.

[Median nerve evoked potentials and explicit memory function during recovery from propofol-sufentanil anesthesia]

OBJECTIVE

In a prospective study rnidlatency somatosensory evoked Potentials (SEP) were investigated in relation to explicit memory function during recovery from propofol/sufentanil anaesthesia.

METHODS

Anaesthesia was maintained in 20 patients with 8 mg kg-1 h-1 propofol and supplemented with sufentanil. SEPs (N20, P25, N35, P45 N50) elicited by median nerve stimulation were recorded at the day before surgery (AWAKE) and during recovery from anaesthesia, when patients were able to identify a shown object (RECOVERY). The day after surgery patients were interviewed about their memory of the recovery period.

STATISTICS

Hotellings' T2.

RESULTS

One day after anaesthesia 9 patients could remember events during the recovery period. At RECOVERY SEP-latencies P45 and N50 were significantly shorter in the patients with recall for the wakeup-phase (p < 0.05).

CONCLUSION

SEP latencies P45 and N50 indicated impaired explicit memory function during recovery from propofol/sufentanil anaesthesia.

Prognostic factors in brain metastases: should patients be selected for aggressive treatment according to recursive partitioning analysis (RPA) classes?

PURPOSE

To determine whether or not Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) derived prognostic classes for patients with brain metastases are generally applicable and can be recommended as rational strategy for patient selection for future clinical trials. Inclusion of time to non-CNS death as additional endpoint besides death from any cause might result in further valuable information, as survival limitation due to uncontrolled extracranial disease can be explored.

METHODS

We performed a retrospective analysis of prognostic factors for survival and time to non-CNS death in 528 patients treated at a single institution with radiotherapy or surgery plus radiotherapy for brain metastases. For this purpose, patients were divided into groups with Karnofsky performance status (KPS) <70% and KPS > or =70%, as proposed by the RTOG.

RESULTS

Median overall survival was 2.9 months (2.0 months for patients with KPS <70% and 3.6 months for patients with KPS > or =70%, p < 0.001). We did not find other variables splitting patients with KPS <70% in different prognostic groups. However, advanced age, multiple brain metastases, presence of extracranial metastases, and uncontrolled primary tumor each predicted shorter survival in patients with KPS > or =70%. When grouped into the original RTOG RPA classes, our data set split into three subgroups with different prognosis and median survival times of 10.5, 3.5, and 2 months, respectively (p < 0.05). Only 3% of patients fell into the most favorable group. Median time to non-CNS death was 4.1 months (12.9 months in RPA class I, 4.9 months in RPA class II, and 3.8 months in RPA class III, respectively, p > 0.05 for RPA class II versus III). However, it was 8.5 months in RPA class II patients with controlled primary tumor, which was found to be the only prognostic factor for time to non-CNS death in patients with KPS > or =70%. In patients with KPS <70%, no statistically significant prognostic factors were identified for this endpoint.

CONCLUSIONS

Despite some differences, this analysis essentially confirmed the value of RPA-derived prognostic classes, as published by the RTOG, when survival was chosen as endpoint. RPA class I patients seem to be most likely to profit from aggressive treatment strategies and should be included in appropriate clinical trials. However, their number appears to be very limited. Considering time to non-CNS death, our results suggest that certain patients in RPA class II also might benefit from increased local control of brain metastases.

Late radiation toxicity after whole brain radiotherapy: the influence of antiepileptic drugs

This retrospective study had the following aims: (a) calculation of actuarial rate of late radiation toxicity after whole-brain radiotherapy (WBRT), (b) correlation of clinical symptoms with changes of computed tomography (CT) scans, and (c) analysis of potentially predictive factors with special regard to concomitant treatment with antiepileptic drugs. We analyzed 49 adult patients, selected from a preexisting data base. Inclusion criteria were as follows: no previous brain irradiation; WBRT without boost; CT, clinical, and neurologic examination before and more than 3 months after completion of WBRT. Uni- and multivariate tests of various patient- and treatment-related parameters as possible predictive factors for clinical symptoms of late radiation toxicity (scored according to the RTOG/EORTC system) as well as cerebral atrophy and white matter abnormalities were performed. Median age was 54 years. Patients were treated for brain metastases (n = 37), primary cerebral lymphoma (n = 2), primary brain tumors (n = 7), or with prophylactic intention (n = 3). Carbamazepine was given to 15 patients, phenytoin to 12, and barbiturate to 7, respectively; 42 patients also received corticosteroids. The median dose of WBRT was 30 Gy (range 27-66 Gy). Median fraction size was 3 Gy (1-3 Gy). Nine patients received two fractions per day. The biologically effective dose (BED) according to the linear-quadratic model ranged between 90 and 141 Gy (median, 120 Gy; alpha/beta value, 1 Gy). Median follow-up was 10 months (range, 4-130 months). In 16 cases, symptoms of late radiation toxicity grade I-III appeared. Actuarial rates were 32% after 1 year, 49% after 2 years, and 83% after 5 years. Actuarial rates of cerebral atrophy were 50% after 1 year and 84% after 2 years (white matter abnormalities: 25% and 85%, respectively). There was a significant correlation between atrophy and white matter abnormalities, but not between CT changes and clinical symptoms. CT changes were dependent on BED, absence of barbiturate use, and preexisting cerebral atrophy. Clinical symptoms usually were dependent on BED too, but treatment with carbamazepine was more important in the multivariate model. Neither other drugs nor other factors influenced late radiation toxicity. A detailed analysis showed that most carbamazepine-treated symptomatic patients took the drug during WBRT as well as during follow-up. Actuarial rates of grade I-III symptoms were 18% versus 50% after 1 year with or without carbamazepine. Even after exclusion of carbamazepine-treated patients, CT changes and clinical symptoms did not correlate. In conclusion, a BED <120 Gy was associated with a lower rate of late radiation toxicity after WBRT. The anticonvulsant drug carbamazepine showed a surprisingly clear influence on clinical symptoms of late radiation toxicity; that might be explained by the fact that the side effects of long-term drug treatment are indistinguishable from mild or moderate true radiation sequelae, rather than that it has a role in the pathogenesis of radiation-induced changes.

Detection of human herpesvirus 6 by reverse transcription-PCR

The role of human herpesvirus 6 (HHV-6) in disease beyond primary infection remains unclear. We have developed and validated a new reverse transcription-PCR (RT-PCR) assay for HHV-6 that can determine the presence of HHV-6 in clinical specimens and differentiate between latent and replicating virus. Peripheral blood mononuclear cells from 109 children were evaluated for HHV-6 by RT-PCR, DNA PCR, and viral culture. Of these samples, 106 were suitable for analysis. A total of 20 samples were positive for HHV-6 by culture and DNA PCR, of which 19 were positive by RT-PCR (sensitivity, 95%). All 28 samples from children that were negative by viral culture, but positive by DNA PCR, were negative for viral transcripts by our RT-PCR assay. One positive RT-PCR result was observed in 56 samples that were negative by tissue culture and DNA PCR. This indicates a low rate of false-positive results (1.2%) and a specificity of 98.8%. This RT-PCR assay can reliably differentiate between latent and actively replicating HHV-6 and should allow insight into the pathogenesis of this ubiquitous virus.

[Implantation metastasis at the exit site after percutaneous endoscopic gastrostomy in esophageal carcinoma]

In patients with esophageal cancer causing obstruction percutaneous endoscopic gastrostomy (PEG) is a well-established procedure with a low complication rate to provide sufficient enteral nutrition. We report on a 68-year-old patient suffering from inoperable squamous cell cancer of the proximal esophagus, who underwent PEG insertion prior to a combined radiochemotherapy. Initially bougienage was performed because of subtotal esophageal stenosis. Four months later a metastasis was found at the PEG exit site with involvement of the gastric wall, most likely caused by spread of tumor cells during insertion of the PEG.

[Palliative accelerated irradiation for advanced non-small-cell lung bronchial carcinoma: results of a pilot study]

In order to reduce the aggressivity of radiotherapy of very advanced non-small-cell lung cancer (NSCLC), and to shorten treatment time, a palliative accelerated irradiation regimen (PAIR) was developed. Before the onset of a randomised study, we performed a one-year pilot study, of which the paper presented here gives the results after complete follow-up. 34 patients (S) with locally inoperable advanced NSCLC stage III (74%) and IV (26%) were irradiated with accelerated fractionation schedule, focussing on tumour and mediastinum, with a total dose of 32 Gy (PAIR, 2 x 2 Gy/d). Treatment results were compared to those of a group of 178 controls (K) treated conventionally, who were selected from a preexisting database according to study inclusion criteria (tab. 2-5 stage III 65%, IV 35%). 105 of them had been treated with a total dose of 60 Gy (K60). After complete follow-up a final evaluation was made. Local control did not differ significantly between both groups, and not between groups S and K60 (tab. 6, fig. 2). Median survival for all patients (S + K) was 6 months. With 8.7 months, that of the study patients (S) was significantly longer than that of the controls (K, fig. 1). This was also true of stage III. Comparison with the 60-Gy-controls (K60) did not reveal significant survival differences. In Cox regression analysis independent prognostic factors were: Karnofsky index, UICC stage, and N stage. Concerning the palliation of tumour-related symptoms, both therapies were comparable (tab. 7). The side-effects were moderate and also comparable. These results induced us start a randomized study comparing both regimens in respect of prognosis and palliation.

18F-deoxyglucose positron emission tomography (FDG-PET) for the planning of radiotherapy in lung cancer: high impact in patients with atelectasis

PURPOSE

18F-deoxyglucose positron emission tomography (FDG-PET) is increasingly applied in the staging of lung cancer (LC). This study analyzes the potential contribution of PET in radiotherapy planning for LC with special respect to tumor-associated atelectasis.

METHODS AND MATERIALS

Thirty-four patients with histologically confirmed LC, who had been examined by PET during pretreatment staging, were included. All were irradiated after CT-based therapy planning with anterior/posterior (AP) portals encompassing the primary tumor and the mediastinum (CT portals, CP). The result of the PET examination was unknown in treatment planning. In retrospect, a PET portal (PP) was delineated and compared with the CP.

RESULTS

In 12/34 cases, the shape and/or size of the portals were changed, primarily (n = 10) the size of the fields was reduced. The median area of CP was 182 cm2 versus 167 cm2 of PP. Seventeen of 34 patients had dys- or atelectasis caused by a central primary tumor. In these cases, differences between CP and PP were significantly more frequent than in the other patients (8/17 vs. 3/17, p = 0.03).

CONCLUSION

In this retrospective analysis, the information provided by FDG-PET would have contributed to a substantial reduction of the size of radiotherapy portals. This applies particularly for patients with tumor-associated dys- or atelectasis.

Effect of combined mouth closure and chin lift on upper airway dimensions during routine magnetic resonance imaging in pediatric patients sedated with propofol

BACKGROUND

In pediatric patients, obstruction of the upper airway is a common problem during general anesthesia. Chin lift is a commonly used technique to improve upper airway patency. However, little is known about the mechanism underlying this technique.

METHODS

The authors studied the effect of the chin lift maneuver on airway dimensions in 10 spontaneously breathing children (aged 2-11 yr) sedated with propofol during routine magnetic resonance imaging. The minimal anteroposterior and corresponding transverse diameters of the pharynx were determined at the levels of the soft palate, dorsum of the tongue, and tip of the epiglottis before and during the chin lift maneuver. Additionally, cross-sectional areas were calculated at these sites, including tracheal areas 2 cm below the glottic level.

RESULTS

Minimal anteroposterior diameter of the pharynx increased significantly during chin lift at all three levels in all patients. The diameters of the soft palate, tongue, and epiglottis increased from 6.7+/-2.8 mm (SD) to 9.9+/-3.6 mm, from 9.6+/-3.6 mm to 16.5+/-3.1 mm, and from 4.6+/-2.5 mm to 13.1+/-2.8 mm, respectively. The corresponding transverse diameter of the pharynx also increased significantly at all three levels in all patients but without significant predominance. The diameters at the levels of the soft palate, tongue, and epiglottis increased from 15.8+/-5.1 mm to 22.8+/-4.5 mm, from 13.5+/-4.9 mm to 18.7+/-5.3 mm, and from 17.2+/-3.9 mm to 21.2+/-3.7 mm, respectively. Cross-sectional pharyngeal areas increased significantly at all levels (soft palate, from 0.88+/-0.58 cm2 to 1.79+/-0.82 cm2; tongue, from 1.15+/-0.45 cm2 to 2.99+/-1.30 cm2; epiglottis, from 1.17+/-0.70 cm2 to 3.04+/-0.99 cm2), including the subglottic level (from 0.44+/-0.15 cm2 to 0.50+/-0.14 cm2).

CONCLUSIONS

This study shows that all children had a preserved upper airway at all measured sites during propofol sedation. Chin lift caused a widening of the entire pharyngeal airway that was most pronounced between the tip of the epiglottis and the posterior pharyngeal wall. In pediatric patients, chin lift may be used as a standard procedure during propofol sedation.

Progressive development of diffuse liver hemangiomatosis

Diffuse liver hemangiomatosis is extremely rare. The etiology and natural history of the disease are unknown. It is also unclear whether tumor growth is induced or modulated by drug therapy. Tumor recurrence after ablative therapy has not been described in patients with diffuse liver hemangiomatosis. Diffuse hemangiomatosis of the left hepatic lobe was suspected in a 35-year-old woman by ultrasonography, CT and hepatic arteriography, and confirmed by laparotomy and biopsies. The patient denied any drug or estrogen use. The tumor was removed by left hepatectomy. Two and six years later, the patient was again hospitalized with progressive tumor growth into the right hepatic lobe. Although diffuse liver hemangiomatosis is a rare disease, its diagnosis should be considered in patients with progressive tumor growth in one or both hepatic lobes. The absence of drug intake or estrogen use does not exclude the diagnosis.

Patients' vs nurses' assessments of postoperative pain and anxiety during patient- or nurse-controlled analgesia

We have compared patients' and nurses' assessments of postoperative pain and anxiety after different analgesic treatments. Sixty orthopaedic patients were allocated randomly to receive i.v. piritramide (either nurse-controlled or patient-controlled) or subarachnoid bupivacaine (nurse-controlled or patient-controlled). Patients and nurses assessed pain and anxiety using a visual analogue scale (VAS; 1-100 mm). Pain and anxiety ratings of patients and nurses were significantly correlated (Spearman's r > or = 0.69; P < 0.001). In general, patients' pain scores were higher than nurses' scores (patients' median VAS = 34 (range 1-76) mm; nurses VAS 21 (1-59) mm) and for all groups except the patient-controlled subarachnoid bupivacaine group, where they were significantly higher (P < 0.01). Discrepancy in pain estimates between patients and nurses increased with the level of pain. The relationship between patients' and nurses' anxiety scores was less clearly defined and did not depend on the level of anxiety.

Hyperfractionated and accelerated-hyperfractionated radiotherapy for glioblastoma multiforme

Because of promising radiobiological advantages allowing dose escalation and/or reduction of treatment time, hyperfractionated and accelerated-hyperfractionated radiotherapy (hf-rt, ahf-rt) were introduced as part of treatment of glioblastoma multiforme (gbm). In December 1988 we started a prospective study of hf-rt (total dose 78 Gy, two daily fractions of 1.3 Gy, interval between daily fractions 6 hr, treatment time 6 weeks, n = 34 patients). The results were compared with our previous regimen of conventionally fractionated radiotherapy (cf-rt: total dose 60 Gy, single dose 2 Gy, treatment time 6 weeks, n = 32 patients). In June 1990, the protocol was modified in order to reduce treatment time (ahf-rt: total dose 60 Gy, two daily fractions of 1.5 Gy, interval 6 hr, treatment time 4 weeks, n = 92 patients until December 1996). No chemotherapy was given. Entry criteria were: age > or = 17 years, pathological diagnosis of supratentorial gbm, and no previous treatment other than surgery. The ahf-rt group included significantly more patients with previous surgical resection instead of biopsy only. Compared with the cf-rt group, both the hf-rt and the ahf-rt group included significantly more patients with frontal tumor location. We found no significant survival difference between the groups (median survival 7-10 months, 1-year survival rate 19%-29%). Progression-free survival, clinical course, and toxicity were also not significantly different. Karnofsky performance status, age, and corticosteroid dose during radiotherapy were the most important prognostic factors. The results of this trial are in large agreement with most previous publications. It demonstrated no improved survival. However, it showed that treatment time can be reduced by ahf-rt without loss of survival benefit or intolerable toxicity. A short radiotherapy course might be appropriate for many patients with gbm who are not suitable for rather aggressive investigational therapies.

Subarachnoid and intravenous PCA versus bolus administration for postoperative pain relief in orthopaedic patients

BACKGROUND

Patient-controlled analgesia (PCA) with intravenous piritramide and subarachnoid bupivacaine was studied during postoperative pain management in comparison with nurse-administered bolus injections.

METHODS

Following general anaesthesia (n = 60) patients randomly received either 3.75-7.5 mg i.v. piritramide on demand (group P-Bolus) or via PCA (group P-PCA; initial bolus: 3.75 mg i.v. piritramide, baseline rate: 1 mg/h, demand-dose 1.5 mg, lockout time: 20 min). Following continuous spinal anaesthesia (n = 60; CSA; 28-G spinal catheter) patients randomly received a subarachnoid injection of 1.5 ml bupivacaine 0.25% every 2-4 h (group B-Bolus) or a baseline infusion of 0.5 ml/h bupivacaine 0.125% plus 0.5 ml bupivacaine 0.125% on demand via PCA (group B-PCA; lockout time: 30 min). Pain ratings were assessed hourly by patients using a visual analogue scale (0 = no pain, 100 mm = unbearable pain).

STATISTICS

multivariate analysis of variance.

RESULTS

While pain scores did not differ between group P-Bolus and P-PCA, group B-PCA showed the lowest pain ratings (18 +/- 22 mm) differing significantly from group B-Bolus (41 +/- 32 mm; P < 0.001). Group P-PCA required more piritramide than group P-Bolus (46 +/- 15 mg vs. 31 +/- 13 mg, P = 0.001). In contrast group B-PCA required less bupivacaine than group B-Bolus (18 +/- 4 vs. 23 +/- 7 mg, P = 0.002).

CONCLUSION

PCA with CSA was more effective than nurse-administered bolus-administration of bupivacaine, while the present study failed to show superiority of i.v. PCA over i.v. bolus-administration of piritramide. PCA using the subarachnoid route is a promising concept for treatment of postoperative pain in orthopaedic patients, while the PCA piritramide regime of this study warrants improvement.

Primary human herpesvirus 7 infection: a comparison of human herpesvirus 7 and human herpesvirus 6 infections in children

OBJECTIVE

To define the clinical and virologic characteristics of primary human herpesvirus 7 (HHV-7) infection and to compare these characteristics with those of primary human herpesvirus 6 (HHV-6) infection.

STUDY DESIGN

A prospective convenience sample study of 496 children < or =3 years old. HHV-7 and HHV-6 infections were identified by viral isolation. Polymerase chain reaction and serology for HHV-7 and HHV-6 were performed. Clinical and laboratory characteristics of patients were obtained from medical records and follow-up interviews.

RESULTS

Children with primary HHV-7 infection (n = 8) were identified and compared with children with primary HHV-6 infection (n = 29) detected during the same time period. All children were febrile (mean temperature 39.8 degrees C) with no difference in the degree of fever, frequency of rash, or gastrointestinal complications between the groups. The median age of children with primary HHV-7 infection was 26 months, significantly older than that of children with primary HHV-6 infection (median, 9 months). Children with primary HHV-7 infection were also more likely than those with primary HHV-6 infection to have seizures associated with the illness (P = .004).

CONCLUSION

Primary infection with HHV-7 can cause a highly febrile illness in childhood, complicated by seizures. The serologic diagnosis of primary HHV-6 and HHV-7 infections may be confounded by cross-reacting antibodies.

Dose/effect relationships for brain metastases

PURPOSE

Only in selected patients with brain metastases, e.g. those with controlled or absent extracranial tumour, may application of higher total doses of radiotherapy improve survival. However, local control is the prerequisite for long-term survival. This study aimed to answer the question whether or not local control can be improved by dose escalation.

METHODS

Computed tomography scans of 322 patients were analysed in order to evaluate the best local result after radiotherapy and the time to local progression. Total doses of 25-60 Gy were administered (single doses 1.8-5 Gy). The biologically effective dose (BED10) was calculated for statistical evaluation according to the linear-quadratic model assuming an alpha/beta-value of Gy. It ranged between 37.5 Gy and 72 Gy.

RESULTS

The best local result was dependent on the number of brain metastases, BED and the histology of the primary tumour (small-cell and breast carcinoma had higher remission rates than squamous-cell carcinoma, non-breast adenocarcinoma and others). Partial remission rates significantly increased with BED, whereas complete remission rates did not improve. Histology was the only significant factor in multivariate tests. The 1-year-failure rate improved with increased BED from 44% to 31% (P > 0.05). Overall survival (median 3 months) was not dependent on total dose.

CONCLUSIONS

Previous studies suggested that a prolongation of survival can be achieved through better local management (e.g. surgery plus radiotherapy, radiosurgery). However, it is still uncertain whether conventional external-beam radiotherapy with higher total doses leads to comparable results. The optimum dose level still has to be established. For squamous-cell carcinoma and adenocarcinoma a BED of at least 72 Gy seems to be necessary, for small-cell and breast carcinoma, doses between 48 Gy and 60 Gy might be sufficient. The important influence of tumour histology on local remission and progression-free survival should be considered when planning future clinical trials.

Multivariate logistic analysis of dose-effect relationship and latency of radiomyelopathy after hyperfractionated and conventionally fractionated radiotherapy in animal experiments

PURPOSE

We examined in rats whether the radiation tolerance of spinal cord is enhanced by using hyperfractionated radiotherapy compared to a conventional schedule. Higher tolerable doses to the spinal cord would allow dose escalation to the tumor and thus possibly lead to higher cure rates, especially in tumors with high cell proliferation.

METHODS AND MATERIALS

Cervical spinal cord of 276 healthy rats was irradiated over 6 weeks hyperfractionally with single doses ranging from 0.75-2.5 Gy up to total doses ranging from 45-150 Gy (60 fractions) and conventionally with single doses of 1.5-4.0 Gy up to total doses of 45-120 Gy (30 fractions). The rats were examined neurologically and sacrificed when paralysis of the hind legs occurred. After fixation, spinal cord was removed and examined histologically. Dose-effect relationship and latency from the beginning of radiotherapy to the onset of paralysis were computed and analyzed using a multivariate logistic regression model.

RESULTS

The model fitted the observed data excellently. There were highly significant effects both for the dose level and for the treatment regimen. Latency analysis showed earlier and more intense acute side effects after hyperfractionation but radiomyelopathy occurred markedly later.

CONCLUSIONS

The sparing effect of hyperfractionation on spinal cord as predicted by radiobiologists could be confirmed in our experiments. Thus, it seems possible to escalate tumor doses using hyperfractionation without enhanced risk to spinal cord but with higher probability of tumor cure.