MRI and proton spectroscopy in a child with Rasmussen's encephalitis. Case report

The greater sensitivity of magnetic resonance spectroscopy (MRS) compared with MRI to brain abnormalities in Rasmussen's encephalitis was demonstrated in a 3-year-old boy. The patient, with symptoms, signs and morphological findings consistent with Rasmussen's encephalitis, was followed with MRI and MRS over 30 months. That metabolic changes can be disclosed by MRS before the development of symptoms or signs was demonstrated as pathological spectra were found not only in the diseased left hemisphere but also in the morphologically normal right hemisphere before any neurological disturbance of that side.

Disseminated infection with Mycobacterium genavense: a challenge to physicians and mycobacteriologists

In the present study we compared the clinical presentations of patients with a clinical diagnosis of AIDS and disseminated Mycobacterium genavense infection (n = 12) with those of patients with AIDS and disseminated M. avium complex (MAC) infection (n = 24). Abdominal pain was seen more frequently in the group of patients infected with M. genavense than in patients infected with MAC (P = 0. 003). Analysis of microbiological data revealed that stool specimens from patients infected with M. genavense were more often smear positive than stool specimens from patients infected with MAC (P = 0. 00002). However, M. genavense could be cultured on solid media from only 15.4% of the stool specimens, whereas MAC could be cultured from 71.4% of the specimens. Bone marrow and liver biopsy specimens yielded growth of M. genavense within a reasonably short time, allowing species identification by DNA technology. Microbiological data clearly demonstrated the importance of acidic liquid medium for primary culture, the avoidance of pretreatment and the use of additives in culture, and the necessity for prolonged incubation if M. genavense is suspected. Susceptibility testing showed that M. genavense is sensitive to rifamycins, fluoroquinolones, and macrolides, whereas it is resistant to isoniazid. Susceptibility to ethambutol and clofazimine could not be evaluated. The mean survival times of patients in the two groups were similar.

Aspiration: a potential complication to vagus nerve stimulation

PURPOSE

Vagus nerve stimulation (VNS) is reported to reduce the frequency of seizures in children and adults without causing serious side effects. However, clinical observation of swallowing difficulties in 2 children treated with VNS made further investigation necessary.

METHODS

Seven patients aged 4-18 years and treated with VNS for 6-14 months were investigated with videoradiography during barium swallow. The children performed 5-30 barium swallow investigations with the VNS device turned off, running as programmed, or set at continuous stimulations. The degree of aspiration was scored from 0 to 3.

RESULTS

In 5 of 7 children, of whom reported transient swallowing difficulties, no change in the degree of aspiration was noted. The 2 children with swallowing difficulties, however. showed increased aspiration score when the stimulator was set at continuous stimulations. In 1 the score also appeared to increase with the VNS running as programmed (p > 0.05). Both children had severe mental and motor disabilities.

CONCLUSIONS

Before and during VNS treatment patients should be evaluated with regard to swallowing problems. There needs to be an easy way to turn the device on and off to avoid aspirations, a hazardous and potentially life-threatening complication of VNS.

Vagus nerve stimulation in 16 children with refractory epilepsy

PURPOSE

Vagus nerve stimulation (VNS) has been reported to produce >90% reduction in the number of seizures in children with intractable epilepsy. These encouraging results need confirmation.

METHODS

Sixteen children, 10 boys and 6 girls aged 4-19 years, were treated with VNS (Cyberonics, Webster, TX, U.S.A.) for 12-24 months. Seizure frequency, seizure severity, changes in quality of life (QOL: visual analogue scale), and side effects were recorded. Eight children had partial and 8 had generalized seizures; 4 of the latter had Lennox-Gastaut syndrome (LGS).

RESULTS

During the tenth to twelfth month of VNS, 6 of 16 children experienced > or =50% reduction in seizure frequency. One girl became seizure-free. Seizure severity showed an average decrease in the score from 15 to 11. After 10 months of treatment, QOL was estimated to have improved > or =50% in 6 of 16 children. Reduction in seizure frequency, decreased seizure severity, and reported improvement in QOL did not entirely coincide. Six children experienced hoarseness, 1 had neck pain, 2 had hypersalivation, 2 experienced tiredness, 2 had aspiration episodes during liquid intake, and 6 had electrical transmission problems; in 4 the problem has been surgically corrected. Five stimulators were turned off due to lack of efficacy.

CONCLUSIONS

Six of 16 children with refractory epilepsy treated with VNS improved, with a reduction not only in seizure frequency but also in seizure severity and in QOL.

Ultrasonographic bedside evaluation of maxillary sinus disease in mechanically ventilated patients

OBJECTIVE

Evaluate A-mode ultrasonographic examination of maxillary sinus disease in mechanically ventilated, critically ill patients using sinoscopy as criterion standard.

DESIGN

Prospective case series.

SETTING

The intensive care units of a tertiary care hospital.

PATIENTS

25 mechanically ventilated, critically ill patients with nasotracheal intubation or a tracheotomy were followed up by ultrasonographic examination of the maxillary sinuses in supine and semirecumbent positions. Infectious sinusitis was suspected in 15 patients, who were bilaterally sinoscoped combined with sampling for bacterial culture.

RESULTS

The frequency of oedema and/or secretions was high: 29 antra of 30 examined. Only 2 of 30 antra showed bacterial infection. Ultrasonographic examinations were sensitive to general pathological changes but less accurate in specific diagnostics such as the presence of secretions (sensitivity for fluid 75%, oedema 81%). The sensitivity of ultrasonographic diagnosis improved when the examination was made in the semirecumbent position (sensitivity for fluid 91%, oedema 81%).

CONCLUSIONS

A-mode ultrasonography is a useful method for daily use, being easy to perform and without discomfort to the patient. It is fast and gives an immediate diagnosis. In intensive care unit patients, it should be the method of choice for day-to-day studies of effects and changes in the upper airways. For the differential diagnosis of oedema and/or secretions, it is not reliable enough to be used as the sole diagnostic method. A complementary investigation, such as computed tomography or sinoscopy, which also provides the opportunity to take samples, is needed for diagnostic confidence.

Survival of European patients with Kaposi's sarcoma as AIDS-defining condition during the first decade of AIDS. AIDS in Europe Study Group

OBJECTIVES

To determine whether the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has changed between 1979 and 1989; and to define whether prognosis factors could be identified.

PATIENTS AND METHODS

This is a multicentric retrospective cohort study from 52 centers in 17 European countries involving adults AIDS patients diagnosed between 1979 and 1989. Variables such as age, sex, geographical regions, transmission groups, date of Kaposi's sarcoma diagnosis, zidovudine use, CD4+ cell count and concomitant opportunistic infections or AIDS-related malignancies were evaluated by using uni- and multivariable proportional hazard models. Log-rank tests were used to determine which variables were associated with survival.

RESULTS

From the 6,546 AIDS patients recruited in the database of the AIDS in Europe Study Group, 1,394 were diagnosed with Kaposi's sarcoma at the time of AIDS diagnosis, from 1979 and 1989. A total of 1,047 Kaposi's sarcoma patients died during the follow-up period. By Kaplan-Meier analyses, the median and mean survival for these Kaposi's sarcoma patients were 17 and 25 months, respectively, with no change over time. However, age, sex (female), geographic region, low CD4+ cell count (< 150 x 10(6)/l) and some opportunistic infections and non-Hodgkin's lymphoma were associated with a poorer prognosis. Zidovudine use, year of diagnosis and risk factor for HIV-1 infection brought no additional information as predictor of mortality.

CONCLUSIONS

This study suggests that the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has remained poor during the last decade in contrast with the overall AIDS survival which had significantly improved from a median of 13-18 months during the same period of observation. There is a need for further prospective information to explain the worse prognosis in women and the geographical variations.

Basaloid squamous cell carcinoma of the maxilla

The study reports the first case of basaloid squamous cell carcinoma (BSCC) involving both the oral mucosa and the tuberosity area of the maxilla. The tumour showed many histological similarities to cases previously reported, though mitoses were not frequent. The immunoreactivity for cytokeratin, S-100, vimentin, Ki-67, p53, c-erbB-2 and bcl-2 was also investigated. Immunostaining for the bcl-2 protein showed a high extent of positive cells, although only a moderate staining intensity. Staining for c-erbB-2 was negative. The pathological findings and the immunoreactivity may indicate that BSCC is not as high a grade carcinoma as previously suggested. Additional studies are thus clearly needed to confirm or reject this impression.

Advanced laryngeal cancer T3-T4 in Sweden: a retrospective study 1986-1990. Survival and locoregional control related to treatment

Different treatment modalities for advanced laryngeal cancer are much discussed in the literature. One-hundred-and-sixty patients with T3-4, N0-3, M0-1 laryngeal cancer diagnosed in Sweden between 1986 and 1990 were retrospectively analysed. One hundred (65 T3: 35 T4) received radical radiotherapy with salvage surgery (RRSS) in case of residual or recurrent disease. Thirty-eight (11T3: 27 T4) patients received surgery with or without radiotherapy (S +/- RT). Twenty-two patients received no treatment. After a median follow up of 4.4 years, the estimated 5-year actuarial corrected survival and 3-year locoregional control were 59% and 44% for T3 RRSS and 47% and 54% for T3 S +/- RT. No significant difference between the different treatment modalities was found. The 5-year corrected survival rate and the locoregional control at 3 years between T4-RRSS (32%; 26%) and T4-S + RT (58%; 68%) groups were significantly different (p < 0.05 and p < 0.01). This might suggest that surgery with or without radiotherapy still has its place as a treatment modality for patients with advanced T4 laryngeal carcinoma.

Characteristics of postischemic seizures in hyperglycemic rats

Normoglycemic animals subjected to 10-20 min of transient ischemia survive without major neurological symptoms, but incur delayed neuronal damage selectively affecting vulnerable neuronal populations. If the animals are hyperglycemic before ischemia is induced, cell damage develops more rapidly, and postischemic seizures appear after a delay of 18-24 h. This study was designed to assess whether the primary insult, i.e., transient ischemia in hyperglycemic animals, triggers early epileptogenic activity which 'matures' into clinical seizures, or if the seizures arise as a result of secondary events occurring after many hours of recirculation. EEG activity during 20-24 h of postischemic recirculation was recorded from electrodes implanted in the neocortex and hippocampus of freely moving rats which had been subjected to 10 min of ischemia under normoglycemic or hyperglycemic conditions. Normoglycemic animals showed a transient postischemic reduction of EEG amplitude and frequency, and sparse and temporary epileptiform activity. In contrast, hyperglycemic animals showed a more pronounced reduction of EEG amplitude and frequency, and early appearing epileptiform activity which was sustained, and ultimately transformed into overt electrographic seizures. The EEG changes were more pronounced in the neocortex than in the hippocampus. The results thus demonstrate that the initial ischemic insult, and not the secondary damage appearing many hours after the initiation of recirculation, triggers epileptiform activity that 'matures' into status epilepticus.

Epidemiology of AIDS-related Kaposi's sarcoma in Europe over 10 years. AIDS in Europe Study Group

OBJECTIVES

To determine the incidence and risk factors associated with Kaposi's sarcoma (KS) occurrence as an AIDS-defining condition or after the diagnosis of AIDS.

DESIGN

Multicentre retrospective cohort study of AIDS in Europe database from 52 clinical centres in 17 European countries.

METHODS

Patients' charts (n = 6546) were reviewed and collected in the database of the AIDS in Europe Study Group from 1979 to 1989. At the time of AIDS diagnosis 1394 patients had KS, whereas an additional 525 others developed KS after AIDS diagnosis. Univariate analysis and development of multivariate models determined factors associated with KS occurrence.

RESULTS

Frequency of KS as an AIDS-defining condition significantly declined over time (P < 0.0001). In our cohort of patients, homo-/bisexual men from central Europe with CD4 cell counts > 150 x 10(6)/l were statistically more likely to develop KS at the time of AIDS diagnosis (P < 0.0001). For patients with an AIDS diagnosis other than KS, the probability of developing KS during the follow-up was 10 and 24% after 12 and 36 months, respectively. Variables significantly associated with a further KS development were transmission group, central European residence, previous herpes simplex infection other than ulcers, and low CD4 cells (< 150 x 10(6)/l). Previous zidovudine therapy had no influence on KS appearance. For patients who developed KS subsequent to AIDS diagnosis, there was no significant decline of the incidence over the 10-year time period.

CONCLUSIONS

This large cohort study clearly shows that demographic data such as sex, transmission group and region of Europe have a major influence on KS development. It also suggests that KS as an AIDS-defining disease occurs earlier in the course of the chronic HIV infection than other opportunistic diseases. Reasons for geographical variations and its declining frequency as an initial AIDS diagnosis remain undetermined.

Primary radiotherapy of T1 and T2 glottic carcinoma--analysis of treatment results and prognostic factors in 223 patients

Treatment results in 223 patients with T1 and T2 glottic carcinoma were analysed. A multivariate analysis was performed to evaluate the prognostic significance of factors related to tumour, patient and treatment. Locoregional control after radiotherapy was 90% for 129 patients with T1 tumours and 73% for 94 with T2 tumours. Disease-specific survival was 96% and 81% for patients with T1 and T2 tumours, respectively. In the multivariate analysis of locoregional control, subglottic extension contributed prognostic information to T-stage. In the univariate analysis, number of involved tumour sites, cord mobility and treatment interruption had a significant influence, which was lost in the multivariate analysis. Age gave additional prognostic information in the multivariate analysis of disease-specific survival. Significant adverse effects of radiotherapy were found in 9 patients (4%). Forty-nine patients (22%) had a second malignancy, 11 (5%) diagnosed before the glottic carcinoma.

Adenoid cystic carcinoma: significance of DNA ploidy

BACKGROUND

DNA ploidy pattern is sometimes used as a prognostic factor. Heterogeneity of a tumor could, however, give false information when a single analysis is performed.

METHODS

Twenty-eight patients with adenoid cystic carcinomas were retrospectively studied with regard to clinico-histologic parameters, and in 24 of these the DNA pattern was assessed using flow cytometry, with multiple analysis from different tumor parts, to determine prognostic factors.

RESULTS

Of the carcinomas, 33% (8/24) were DNA aneuploid, and 17% (4/24) of the tumors showed intratumoral heterogeneity of DNA content; two of them with mixture of diploid and aneuploid stemlines. The DNA aneuploid tumors were clinically more advanced and demonstrated a higher frequency of solid architecture than did diploid tumors (p < 0.05). The S-phase values were significantly higher in aneuploid samples than in diploid ones (p < 0.05). The recurrence rate was significantly higher in patients with aneuploid tumors (75%) than with diploid ones (19%) (p < 0.05). The cumulative survival was worse for patients with aneuploid tumors than for those with diploid ones (p < 0.05).

CONCLUSIONS

Our findings suggest a potentially important role for flow cytometry in evaluation of adenoid cystic carcinoma. It is of interest to observe that in some tumors both diploid and aneuploid stemlines can co-exist. If one sample is analyzed and demonstrates diploid cells, there is a 3% chance that the tumor is also heterogeneous with aneuploid stemlines. If one sample demonstrates aneuploid cells, there is a 7% chance for heterogeneity with diploid cells, as well. Two samples from different tumor parts can be considered representative.

Providing residents with a comprehensive educational program in outpatient psychiatry : integrating an outpatient curriculum into outpatient management teams

As part of their efforts to prepare psychiatry residents for comprehensive, practical outpatient psychiatric practice, the authors have established an organized training program in ambulatory psychiatry. The program consists of outpatient management teams that run from mid-PGY-2 to PGY-4, a specified minimum number of mandatory outpatient hours for continuity patient care, and suggested guidelines for residents' outpatient experiences. An outpatient management team curriculum has been designed for team leaders and trainees that consists of specific topics in outpatient care, associated learning objectives, and readings for each topic. This curriculum, which supplements our previous program of conferences, individual supervision, and a yearlong psychotherapy seminar series, has been refined over the past 5 years. The authors describe the program and the topics included in the curriculum.

Possible errors in diagnosis of bacterial sinusitis in tracheal intubated patients

Bacterial sinusitis is recognized as a complication of prolonged nasotracheal intubation. Verification of the diagnosis, however, requires culture findings from a "true" sample from the maxillary antrum. A "true" antral sample can only be obtained after passing either the nasal or oral mucosae with their rich aerobic and anaerobic bacterial flora. No properly controlled study has been made into the problem of contaminated samples in bacterial sinusitis complicating prolonged nasotracheal intubation. The design of the study was a case series in an intensive care unit. The patients had either had endotracheal tube or tracheal cannula for seven days or were septic, having an endothracheal tube or a tracheal cannula and therefore due to an investigation of infection foci. Antral cultures obtained via the canine fossa were compared with oral cultures to exclude the contribution of oral bacterial contamination and thereby to improve the reliability of diagnosis based on culture results. The contamination rate was lowered significantly from 67% to 5% when an area of free bone was prepared in the canine fossa thus avoiding instrument contact with the oral mucosa. A high contamination risk can be dealt with by adjusting the technique of sampling thereby increasing the culture reliability.

Preischemic hyperglycemia leads to delayed postischemic hyperthermia

BACKGROUND AND PURPOSE

Temperature alterations are known to influence the outcome of transient ischemia, even when instituted in the postischemic period. Since preischemic hyperglycemia aggravates ischemic brain damage, the question of whether hyperglycemic animals become hyperthermic arose. To explore this possibility, we measured body temperature telemetrically in normoglycemic and hyperglycemic rats subjected to 10 minutes of forebrain ischemia at a body (and brain) temperature of 37 degrees C.

METHODS

Isoflurane-anesthetized animals were subjected to 10 minutes of forebrain ischemia under normoglycemic or hyperglycemic conditions. Temperature changes after ischemia were measured by means of a telemetric temperature coil.

RESULTS

In normoglycemic animals, temperature decreased to 35.6 +/- 1.1 degrees C (mean +/- SD) during the first 4 hours of recovery, after which it gradually increased to normal values (38 degrees C). Hyperglycemic animals behaved differently in that they remained normothermic for approximately 10 hours during recovery and later became hyperthermic, with core temperatures rising above 39 degrees C. The rise in temperature was not due to the osmotic load of the glucose administered because infusion of mannitol, which gave a comparable increase in plasma osmolality, failed to cause delayed postischemic hyperthermia. Excessive hypercapnia during ischemia in normoglycemic animals, which produces cerebral acidosis of a magnitude similar to that of hyperglycemia and is known to aggravate ischemic lesions, likewise failed to induce hyperthermia. When post-ischemic seizures ensued in hyperglycemic subjects, temperature was 39.8 +/- 0.6 degrees C. Animals with seizures invariably died. To evaluate the influence of postischemic hyperthermia on the outcome, an additional series of experiments was performed in which delayed hyperthermia was avoided by gentle cooling (n = 6) or by acetaminophen administration (n = 5). Although these procedures prevented delayed hyperthermia, they neither blocked seizure induction nor affected the fatal outcome. Postischemic seizures developed when the core temperatures of animals were 37.9 +/- 0.1 degrees C and 37.8 +/- 0.2 degrees C in the cooled and acetaminophen-treated groups, respectively.

CONCLUSIONS

The results suggest that both delayed hyperthermia and delayed seizures in hyperglycemic animals are caused by the aggravated damage incurred by these animals during or immediately after the ischemic insult.

Hyperthermia aggravates and hypothermia ameliorates epileptic brain damage

The influence of hyperthermia and hypothermia on epileptic brain damage was studied in rats, in which status epilepticus was induced by flurothyl. Histopathological changes were examined by light microscopy after 1 or 7 days of recovery. Two series of animals were studied. In the first, short periods of seizures (20 and 25 min) were employed to examine whether moderate hyperthermia (39.5 degrees C) would aggravate epileptic brain damage, and a longer period (45 min) was used to investigate whether moderate hypothermia (32.5 degrees C) would ameliorate the damage. The second series investigated whether brief periods of status epilepticus (10 min) would cause brain damage if hyperthermia were high or excessive. For this series, animals with body temperatures of 37.0, 39.0, and 41.0 degrees C were studied. Data from normothermic animals (37.5 degrees C) confirmed previously described neuronal damage. Although hyperthermic animals failed to show increased damage in the CA1 sector, or in the hilar region of the dentate gyrus, they showed enhanced damage in the neocortex and globus pallidus (GP). In substantia nigra pars reticulata (SNPR) four out of five hyperthermic animals had bilateral infarcts after 20 min of status epilepticus, whereas no normothermic animal showed such damage. Hypothermia seemed to ameliorate epileptic brain damage in the neocortex (n.s.) and GP (P < 0.05) following status epilepticus for 45 min. Three out of seven hypothermic animals had mild SNPR involvement compared to severe infarction of the nucleus in five out of six normothermic animals (P < 0.05). Thus, hyperthermia aggravated and hypothermia ameliorated epileptic brain damage both in regions showing selective neuronal necrosis (neocortex) and in regions developing pan-necrosis (GP and SNPR). The second series displayed an unexpected result of excessive hyperthermia. Animals subjected to only 10 min of status epilepticus at a temperature of 41 degrees C showed not only neocortical lesions, but also moderate to extensive damage to the hippocampus (CA1, subiculum, and dentate gyrus). It is concluded that at high body and brain temperature, brief periods of status epilepticus can yield extensive brain damage, primarily affecting the hippocampus.

Controversies in the management of laryngeal cancer: results of an international survey of patterns of care

Cancer of the larynx is the most prevalent non-cutaneous malignancy of the head neck region and its treatment presents a threat to both natural speech and survival. This study examines the manner in which two separate specialties in the same and different geographic regions vary in their opinions about the treatment of glottic laryngeal cancer. The goal was to define options available to patients and to classify controversies about optimal treatment which might be resolved in clinical trials. Questionnaires depicting different presentations of glottic larynx cancer were mailed to 1649 otolaryngologists and radiation oncologists in North America, Europe and Australasia. Half the doctors were asked to describe their preferred treatment for a patient while the others were asked to imagine that they themselves were the patient. In all the disease situations opinions varied significantly with respect to the treatment modality advised (whether to employ surgical or radiotherapy approaches) and in more extensive disease situations the intention of treatment also varied depending on whether a curative approach should involve conservation or loss of the larynx. Doctors also recommended similar treatment for their patients as they would for themselves. Apart from disease extent the most significant variables influencing recommendations were the physicians' specialty (P = 0.0001) and where they practice (P = 0.0001). These findings demonstrate diversity of opinion which is influenced more profoundly by the traditions of the specialties and geographic location of practice than by the reported results of treatments for laryngeal cancer. Convictions about optimal management have become barriers to the assessment of the relative value of different treatments and to ensuring that patients are fully informed about management options. The profession should regard as a high priority efforts to resolve these therapeutic conflicts which are associated with major differences in quality of life.

The dynamics of local tissue damage induced by Bothrops asper snake venom and myotoxin II on the mouse cremaster muscle: an intravital and electron microscopic study

The acute tissue damaging effects of Bothrops asper snake venom and a myotoxic Lys-49 phospholipase A2 (myotoxin II) on the mouse cremaster muscle were studied by intravital and electron microscopy. Both venom and myotoxin induced local contractions of the muscle fibres within 10-60 sec after exposure, which disappeared after 1-2 min. This observation is consistent with the hypothesis that Bothrops myotoxins act initially at the sarcolemma by affecting its permeability and allowing an influx of calcium. The venom also induced an early but transient vasoconstriction of arterioles. The development of edema was monitored using i.v. FITC-dextran as a marker. Plasma leakage started after about 2 min of exposure to venom or myotoxin, was extensive by 4-5 min, and originated from small venules and their adjoining capillary segments. The venom induced formation of thrombi and emboli in venules, but not in arterioles. Haemorrhage appeared after 4-6 min of exposure, the bleedings always originating from capillaries and small venules. The microbleedings were explosive, appearing as rapid bursts of erythrocytes into the extravascular space, and suggesting a per rhexis type of haemorrhage. This was confirmed by electron microscopy evaluation of the same microvessels observed intravitally, which showed erythrocyte extravasation through gaps in damaged endothelial cells. Other phenomena in the microcirculation included blood-flow disturbances, crenation and sphering of erythrocytes, and stasis with dense packing of cells in capillary networks. Muscle necrosis, caused by either venom or myotoxin, started 3-4 min after application. The first sign of damage in the fibres was the development of a narrow, transverse band with local loss of striation. This was followed by slow retraction of myofibrils until there was a complete transverse rupture of the fibre. This process was often repeated along the same fibre, leaving a row of fragments separated by spaces apparently devoid of myofibrillar material. The results confirm the rapid tissue damaging effects of B. asper venom, implying that potentially useful blocking agents must be administered early and have the ability to diffuse rapidly into the tissues.

Heterogeneity of salivary gland tumors studied by flow cytometry

Intratumor DNA heterogeneity was investigated by flow cytometric analysis of multiple samples taken from different sites of 8 benign and 16 malignant primarily resected salivary gland tumors. All benign tumors had diploid DNA content. The overall incidence of DNA diploidy in 16 malignant cases examined was 50%. Intratumor differences in DNA ploidy were observed in four malignant tumors (25%); 2 of these 4 heterogeneous tumors contained both aneuploid and diploid cell clones. The remaining 12 tumors showed a homogeneous DNA content in the different specimens; 8 were diploid, 3 aneuploid, and 1 was polypoid. The DNA nondiploid tumors were clinically more advanced than the DNA diploid ones (p < 0.01). The tumor proliferation rate (fraction of cells in S-phase) was higher in DNA nondiploid samples than in diploid ones (p < 0.01). The DNA nondiploid tumors seemed to recur more often than DNA diploid ones did. The data emphasize the usefulness of DNA measurements for the characterization of malignant salivary gland tumors but also the importance of adequate sampling in assessing their DNA ploidy.

Effects of dimethylthiourea on ischemic brain damage in hyperglycemic rats

Hyperglycemia is known to worsen the outcome of transient global or forebrain ischemia. The aggravating effect is believed to be mediated by the additional formation of lactate- and of H+. Recent evidence suggests that reactive oxygen species contribute to the damage after brain ischemia. Since acidosis accelerates free radical damage in vitro, we decided to explore if ischemic damage in hyperglycemic subjects is ameliorated by dimethylthiourea (DMTU), an established free radical scavenger. In one series of hyperglycemic rats, we studied whether preischemic administration of DMTU alters the clinical outcome, notably the incidence and frequency of seizures. In two different series, the effect of DMTU on tissue damage was assessed by light microscopy after 15 h of recovery. Longer periods could not be studied since seizures developed. In the first of these series the animals were anesthetized with isoflurane, and in the second with halothane. The latter anesthesia largely suppressed the "early" postischemic seizures, i.e. those occurring after 1-4 h. Dimethylthiourea treatment altered the clinical outcome after ischemia. Thus, the "late" postischemic seizures appeared milder and occurred significantly later than in untreated animals. The fatal outcome was also delayed since treated animals died after 35.5 +/- 8.2 h (mean +/- SD) of recirculation, as compared to 19.8 +/- 3.6 h of recirculation in control animals. However, all DMTU-treated (and control) animals died. In the first morphological series (isoflurane anesthesia) the histopathological analysis was complicated by the occurrence of prefixation seizures; such seizures were recognized in 4/16 animals. When these 4 animals were excluded from the analysis (2 treated and 2 control animals), DMTU pretreatment did not ameliorate the damage, except in the substantia nigra pars reticulata (P < 0.05). In the second series, comprising animals anesthetized with halothane, only one animal out of 16 had "early" seizures, and none showed "late" seizures before death. Among these animals DMTU treatment significantly ameliorated damage to caudoputamen and cingulate cortex (P < 0.01). We conclude that treatment with the free radical scavenger DMTU partly ameliorates ischemic brain damage associated with excessive acidosis, and marginally delays the development of post-ischemic seizures. However, the effects were moderate and could, at least in part, have been caused by nonspecific effects of DMTU. Furthermore, all DMTU-treated animals died. The results thus give little support to the notion that the aggravating effects of acidosis is due to enhancement of free radical production.

Ischemic brain damage is not ameliorated by 1,3-butanediol in hyperglycemic rats

BACKGROUND AND PURPOSE

Treatment with the ketone body precursor 1,3-butanediol has been suggested to ameliorate hypoxic/ischemic brain damage. Butanediol could provide an alternative energy substrate for the brain, thereby decreasing the amount of glycolytically produced lactate. Hyperglycemia aggravates brain damage after brain ischemia and causes fatal postischemic seizures, probably by increasing the production of lactate and decreasing the pH. We studied whether butanediol treatment altered the adverse consequences following ischemia complicated by hyperglycemia.

METHODS

Hyperglycemic adult male rats were given 25 or 50 mmol.kg-1 body wt butanediol intravenously 30 minutes before 10 minutes of transient forebrain ischemia. Morphological evaluation was performed following perfusion-fixation after 15 hours of recovery. Blood concentrations of beta-hydroxybutyrate, acetoacetate, glucose, and lactate and brain tissue concentrations of energy metabolites were measured before and after ischemia.

RESULTS

Blood levels of ketone bodies increased in the butanediol-treated rats. Ischemia decreased the blood levels of acetoacetate but increased the levels of beta-hydroxybutyrate by a similar amount, resulting in unchanged high levels of total ketone bodies in the animals that received butanediol. Brain tissue levels of glucose, energy metabolites, and lactate showed no difference between butanediol- and saline-treated rats. Furthermore, compared with saline-treated animals butanediol-treated rats showed no decrease in brain damage and no attenuation in the development of postischemic seizures.

CONCLUSIONS

The ketone body precursor 1,3-butanediol offers no protective effect in transient forebrain ischemia complicated by hyperglycemia.

Frontal cortex lesion prior to hyperglycemic ischemia: no decrease in ensuing substantia nigra pars reticulata damage or fatal post-ischemic seizures

Preischemic hyperglycemia worsens brain damage after ischemia, and characteristically leads to post-ischemic seizures and a pan-necrotic lesion in substantia nigra pars reticulata (SNPR). The excitatory input to SNPR could contribute to the damage observed. By performing a unilateral frontal cortex lesion 6-19 days prior to the ischemia, we wanted to explore whether a decrease in excitatory input to the ipsilateral SNPR ameliorate the seizures or alter the light microscopical damage in SNPR. Our results demonstrate that unilateral frontal cortex lesion did not alter the development of fatal post-ischemic seizures after 10 min of ischemia in hyperglycemic subjects. Thus, 7/8 animals developed seizures and died within 20 h of recovery. This study also failed to show any difference between the left and right side in post-ischemic SNPR damage after 15 h of recovery in animals with preischemic unilateral frontal cortex lesion. Furthermore, no side difference was observed in any other brain region evaluated. The results thus suggest that the pan-necrotic lesion in SNPR after hyperglycemic ischemia is not caused by excessive excitatory input from frontal cortex. A decrease in the GABA-ergic inhibitory input from caudoputamen to SNPR may be a more important mechanism for the ensuing excitotoxic post-ischemic SNPR damage, and for seizure development.

Acidosis-induced ischemic brain damage: are free radicals involved?

Substantial evidence exists that reactive oxygen species participate in the pathogenesis of brain damage following both sustained and transient cerebral ischemia, adversely affecting the vascular endothelium and contributing to the formation of edema. One likely triggering event for free radical damage is delocalization of protein-bound iron. The binding capacity for some iron-binding proteins is highly pH sensitive and, consequently, the release of iron is enhanced by acidosis. In this study, we explored whether enhanced acidosis during ischemia triggers the production of reactive oxygen species. To that end, enhanced acidosis was produced by inducing ischemia in hyperglycemic rats, with normoglycemic ones serving as controls. Production of H2O2, estimated from the decrease in catalase activity after 3-amino-1,2,4-triazole (AT) administration, was measured in the cerebral cortex, caudoputamen, hippocampus, and substantia nigra (SN) after 15 min of ischemia followed by 5, 15, and 45 min of recovery, respectively (in substantia nigra after 45 min of recovery only). Free iron in cerebrospinal fluid (CSF) was measured after ischemia and 45 min of recovery. Levels of total glutathione (GSH + GSSH) in cortex and hippocampus, and levels of alpha-tocopherol in cortex, were also measured after 15 min of ischemia followed by 5, 15, and 45 min of recovery. The results confirm previous findings that brief ischemia in normoglycemic animals does not measurably increase H2O2 production in AT-injected animals. Ischemia under hyperglycemic conditions likewise failed to induce increased H2O2 production. No difference in free iron in CSF was observed between animals subjected to ischemia under hyper- and normoglycemic conditions. The moderate decrease in total glutathione or alpha-tocopherol levels did not differ between normo- and hyperglycemic animals in any brain region or at any recovery time. Thus, the results failed to give positive evidence for free radical damage following brief periods of ischemia complicated by excessive acidosis. However, it is possible that free radical production is localized to a small subcellular compartment within the tissue, thereby escaping detection. Also, the results do not exclude the possibility that free radicals are pathogenetically important after ischemia of longer duration.