Magnetic resonance imaging of acoustic schwannomas

The magnetic resonance imaging (MRI) findings of 27 histologically proven acoustic schwannomas in 24 patients (13 men, 11 women, age 20-79 yr) are described in detail. Three patients had bilateral tumors. Twenty-two tumors (82%) had intra- and extracanalicular components, three tumors (11%) were limited to the internal auditory canal (IAC) and two tumors (7%) were limited to the cerebellopontine angle (CPA). The diameters of extracanalicular lesions in the CPA ranged from 12 to 50 mm, and most of them were round in shape. All IAC portions of CPA tumors had a funnel-shaped appearance on the axial images and short-club-shaped configuration on the coronal images. There was strong homogeneous contrast enhancement of the solid components in 12 tumors (44%) and heterogeneous enhancement in 15 tumors (56%). The cystic components of the tumors correlated well with the histologic features. All tumors could be demonstrated in their enterity by MRI. The "short-club sign", first described in this study, helped to confirm the intracanalicular component of acoustic schwannomas, which were usually found in the cerebellar cistern. The results of this study show that MRI is a sensitive imaging modality for the assessment of acoustic schwannomas located at the CPA or IAC, or in both regions. MRI is non-invasive and does not involve ionizing radiation. It should be considered the imaging examination of choice to evaluate patients with suspected acoustic schwannomas.

Magnocellular and parvocellular divisions of pigeon nucleus isthmi differentially modulate visual responses in the tectum

The electrophysiological responses of 162 tectal cells to computer-generated visual stimuli were extracellularly recorded from 24 homing pigeons before and after injecting either lidocaine or N-methyl-D-aspartate (NMDA) into the nucleus isthmi pars magnocellularis (Imc) or the nucleus isthmi pars parvocellularis (Ipc). Micro-injections of lidocaine into Imc resulted in a significant reduction of firing rate in 80% of tectal cells, whose excitatory receptive fields (ERFs) were localized within the ERF of the Imc cell where the lidocaine was injected. In contrast, when lidocaine was injected into Ipc under identical circumstances it had no effect on the visually driven activity of 68% of tectal cells. However, when the excitatory amino acid NMDA was injected into Ipc it produced a significant reduction in the visually driven firing of 75% of tectal neurons when their ERFs were within the isthmic ERF, while similar application of NMDA into Imc had no effect on the visually driven response of 94% of tectal neurons. When the ERFs of tectal cells were localized outside the ERF of the isthmic cell where the chemical was injected, Imc-injected lidocaine had no effect in 9 out of 10 tectal cells, whereas Ipc-injected NMDA increased firing in 7 out of 17 tectal cells. Therefore, it is suggested that the Imc-tectal fibers participate in a positive feedback pathway and the Ipc-tectal fibers are involved in a negative feedback pathway.

Expression of heat-stable antigen on tumor cells provides co-stimulation for tumor-specific T cell proliferation and cytotoxicity in mice

Heat-stable antigen (HSA/J11d/possibly homologous to CD24), a cell adhesion molecule capable of providing a co-stimulatory signal for T cell proliferation, is expressed on B cells, activated T cells, monocytes, granulocytes, Langerhans cells and thymocytes. Recent studies have demonstrated that co-stimulatory signals provided by cell adhesion molecules such as B7-1 play an essential role in generation of an anti-tumor immune response. To examine whether the co-stimulatory signal provided by HSA can induce an anti-tumor immune response, we have transfected HSA cDNA into the murine melanoma cell line K1735M2, and examined the ability of this transfected cell line to induce tumor-specific T cell responses. The results demonstrate that spleen cells from mice immunized with HSA-transfected K1735M2 cells showed enhanced T cell proliferation in a mixed lymphocyte tumor reaction (MLTR) assay and also demonstrated a significant anti-tumor cytotoxicity to the parent tumor cell (K1735M2). This anti-tumor cytolytic activity could be abrogated by pretreatment of effector cells with anti-mouse CD8 monoclonal antibody and complement. Under similar conditions, spleen cells from C3H mice immunized with vector-transfected K1735M2 cells neither actively proliferate in an MLTR assay, nor did they exert significant cytolytic activity against the respective tumor cells. In summary, our study demonstrated that HSA can provide a co-stimulatory signal for the T cell immune response against tumor cells in a murine model.

Brown-Séquard syndrome associated with Horner's syndrome in cervical epidural hematoma

STUDY DESIGN

This report analyzed the likely locations of lesions that cause a combination of Horner's and Brown-Séquard syndromes. One must know the anatomic structure of spinal cord and the sympathetic nerve chain.

OBJECTIVES

A hypertensive patient had Brown-Séquard and Horner's syndromes after neck trauma. The magnetic resonance imaging and surgical findings showed the correlation between the clinical symptoms and the likely lesion.

METHODS

The patient underwent right hemilaminectomy from C2 to C6 with total removal of hematoma.

CONCLUSION

The spinal epidural hematoma rarely is a surgical emergency. The patient presented with Brown-Séquard and Horner's syndromes. Magnetic resonance imaging made a rapid and correct diagnosis. The patient received an emergent right hemilaminectomy from C2 to C6 with removal of hematoma and subsequently made a complete recovery.

Comparison of APACHE III, II and the Glasgow Coma Scale for prediction of mortality in a neurosurgical intensive care unit

OBJECTIVES

This study examined the efficacy of predicting power for hospital mortality of three different scoring systems in a neurosurgical intensive care unit (NICU).

SETTING

An eight-bed NICU in a 1,270-bed medical centre (Taichung Veterans General Hospital).

SUBJECTS

Two hundred patients with head injury, brain tumour, hypertensive intracerebral haemorrhage, rupture of aneurysm or arteriovenous malformation, or other categories were included in our study in a consecutive period of 14 months. Patients less than 14 years old were not included.

DESIGN

On the first day of admission, data were collected from each patient to compute the Acute Physiology and Chronic Health (APACHE) II and III, and Glasgow Coma Scale (GCS) scores. Hospital mortality was defined as when death occurred before discharge from hospital.

INTERVENTIONS

none.

MEASUREMENTS

Sensitivity, specificity and correct prediction outcomes were measured by logistic regression in three scoring systems. The Youden index was also obtained. The best cutoff point in each scoring system was determined by logistic regression or by the Youden index. Data obtained by logistic regression were compared by McNemar's test. The differences in Youden index were calculated by the Student's t-test. The area under the Receiver Operating Characteristic (ROC) curve was computed and the area of each scoring system was then compared by the Wilcoxon Mann-Whitney test.

MAIN RESULTS

The correct prediction of outcome was 85.5% in APACHE III, 77.5% in APACHE II and 75.0% in GCS. The area under the Receiver Operating Characteristic (ROC) curve was 0.892 in APACHE III, 0.826 in APACHE II and 0.868 in GCS. For the prediction of dead patients at the best cutoff point, APACHE III and GCS were better than APACHE II, (both p < 0.01 respectively). For the prediction of alive patients at the best cutoff point, APACHE III was better than GCS and APACHE II (p < 0.01 respectively).

CONCLUSION

The APACHE III system seems to be the most reliable. The results reveal that the APACHE III system is better in predicting power for hospital mortality than either the GCS or APACHE II systems in our NICU patients.

Epidemiological study of head injuries in central Taiwan

BACKGROUND

Head injury plays a major role in emergency neurosurgery and is the leading cause of neurosurgical mortality at Taichung Veterans General Hospital. Statistical data show that a similar condition exists in other teaching hospitals in the central Taiwan area, which includes more than one-quarter of the entire population and has more than one-third of the total land of Taiwan. A clinical statistical survey of head injuries in this area may provide a better understanding of the realistic situation in Taiwan. Reports on head injuries in Taipei City, Taipei area, and Hualian County are also cited for comparison.

METHODS

The present study is based on a cooperative investigation of head injuries by 18 teaching hospitals in central Taiwan from July 1991 to June 1993. All patients received a neurological examination including the Glasgow coma scale (GCS), with recording by 20 Board-certified neurosurgeons.

RESULTS

The 7050 cases collected included 5322 hospitalized cases, 1694 cases seen in the Emergency Room, and 34 deaths on arrival. The leading cause of head injuries was traffic accidents (5354 cases, 76.3%). Motorcycles contributed to the highest number of cases (3661, 68.4%); and trains contributed to the lowest number (8, 0.1%). Helmets were used in only 5.2% of 3503 motorcycle accidents. Based on the patients' or families' description in 4835 cases, the leading cause of the accident was careless driving (1180 cases, 24.4%). The 1088 cases of severe head injury were classified with a score less than 8 by the GCS; 498 of them died, or an 86.6% mortality (575 cases).

CONCLUSIONS

Traffic accidents are the leading cause of head injuries, and motorcycles contribute to the major part of it in central Taiwan. Similar conclusions can be drawn for other areas including Taipei City, Taipei area, and Hualian County.

Decompressive craniotomy for acute shaken/impact baby syndrome

To estimate the surgical efficacy of decompressive craniotomy, 23 children under 2 years of age with acute shaken/impact baby syndrome were treated with medical or surgical methods over the past 6 years. Six children (group A) with lower intracranial pressure (ICP, less than 30 mm Hg) were treated with medical therapy, and 17 children with high ICP (more than 30 mm Hg) of which 7 children were treated with medical therapy (group B) and another 10 children (group C) were treated with decompressive craniotomy. Bifrontal craniotomy was performed on 5 children with generalized brain swelling. A large frontotemporoparietal craniotomy was performed on another 5 children with unilateral swelling. A mean of 32 ml of subdural hematoma was removed. The mean ICP was reduced by 80% in the craniotomy group, p < 0.05. Children in groups A and C performed better on the Children's Outcome Scale than those in group B, p < 0.05. Mortality was significantly lower (0/10) in group C than in group B (3/7), p < 0.05. Hearing preservation was better in group C than in group B, p < 0.05. Bifrontal and frontotemporoparietal craniotomies may reduce mortality and morbidity for acute shaken/impact baby syndrome with high ICP. Patients with ICP less than 30 mm Hg may be treated successfully with medical therapy and patients with ICP more than 30 mm Hg are better treated with decompressive craniotomy.

Dose-dependent effects of chronic amphetamine administration in local cerebral glucose utilization in rat

The daily dose of amphetamine pretreatment may affect the development of behavioral-sensitized patterns in rodents and amphetamine psychosis in humans. This experiment investigated the regional cerebral metabolic changes in rats after pretreatment with different doses of amphetamine by the 2-[14C]deoxyglucose method. Rates of local cerebral glucose utilization were examined in 37 regions of the rat brain. The result showed generally maximal metabolic augmentation in the 5.0 mg/kg group instead of in the 1.0 or the 10.0 mg/kg groups. Behavioral testing using motor activity cages in rats with the same regimen found no difference among groups. The findings demonstrate that there might be a window effect by daily amphetamine dose on the development of drug dependence and amphetamine psychosis. It was suggested that the 2(-)[14C]deoxyglucose method could be used for further study of animal models of amphetamine psychosis.

The study of pollen and Der p mite-specific IgE antibodies in children with allergic rhinitis

The role of pollens and house dust mites in perennial chronic rhinitis has been investigated for the Taipei area. Fifty-four serum specimens were collected from children with chronic rhinitis. EIA kits (Phadezyme RAST) were used to detect specific IgE antibody of nine allergens, including house dust mite (Der p) and eight common pollens. The children were divided into allergic (AR) and nonallergic (NAR) groups, based on the results of skin tests, inhalant allergen-specific IgE screen (Phadiatop), physical examination, past history and family history. The results showed: (1) 41 (76%) patients were defined as allergic rhinitis; (2) Der p specific IgE was detected in 41 (100%) AR patients and 7 (54%) NAR patients (P < 0.005), a strong positive reaction (> 2+) in 83% AR and none NAR patients (P < 0.005); (3) one, or more than one, pollen-specific IgE were found in 13 (32%) AR and 4 (31%) NAR patients. No strong positive reaction was detected in either group.

THE CONCLUSION

(1) three-fourths of the children with chronic rhinitis are allergic by nature; (2) house dust mite is the major allergen of allergic rhinitis; (3) in the Taipei area, pollen does not play an important role for children with allergic rhinitis.

Mammalian DNA ligase II is highly homologous with vaccinia DNA ligase. Identification of the DNA ligase II active site for enzyme-adenylate formation

Mammalian cells contain three biochemically distinct DNA ligases. In this report we describe the purification of DNA ligase II to homogeneity from bovine liver nuclei. This enzyme interacts with ATP to form an enzyme-AMP complex, in which the AMP moiety is covalently linked to a lysine residue. An adenylylated peptide from DNA ligase II contains the sequence, Lys-Tyr-Asp-Gly-Glu-Arg, which is homologous to the active site motif conserved in ATP-dependent DNA ligases. The sequences adjacent to this motif in DNA ligase II are different from the comparable sequences in DNA ligase I, demonstrating that these enzymes are encoded by separate genes. The amino acid sequences of 15 DNA ligase II peptides exhibit striking homology (65% overall identity) with vaccinia DNA ligase. These peptides are also homologous (31% overall identity) with the catalytic domain of mammalian DNA ligase I, indicating that the genes encoding DNA ligases I and II probably evolved from a common ancestral gene. Since vaccinia DNA ligase is not required for DNA replication but influences the ability of the virus to survive DNA damage, the homology between this enzyme and DNA ligase II suggests that DNA ligase II may be involved in DNA repair.

Repeat operations in failed microvascular decompression for trigeminal neuralgia

For the study of pathogenesis and treatment of recurrent trigeminal neuralgia, we performed 31 repeat operations from among 400 patients with trigeminal neuralgia in the past 10 years. Initially, of these 400 patients, 376 underwent microvascular decompression only, and 24 underwent partial sensory rhizotomy with or without microvascular decompression. Fifty-three patients (14%) had recurrences after microvascular decompression, of which 31 patients underwent repeat operations. Among the repeat operations, there was negative exploration in 16 patients (52%), arterial loop compression in 7 (22%), venous compression in 4 (13%), and Teflon compression or adhesion in 4 (13%). Twenty-one patients had early recurrences within 1 year, and 10 patients had late recurrences. Negative exploration and arterial compression were more likely in early recurrence (P = 0.01). Continuing demyelination might occur in patients with negative exploration, even when adequate decompression had been initially performed. Seventy percent of the patients had no recurring pain by way of partial sensory rhizotomy for negative explorations, redecompression of arterial loops, division of offending veins, or lysis and reposition of Teflon. About half of the patients had positive findings that were amenable without rhizotomy in the repeat operations. A repeat operation for failed microvascular decompression is a good choice if the condition of the patient is tolerant.

Brachial plexus neuropathy secondary to septic arthritis and osteomyelitis: report of two cases

Two infants, delivered uneventfully, later developed right brachial plexus palsy secondary to pyogenic osteomyelitis and arthritis of the right shoulder joint. Weakness of right arms occurred at the sixth and tenth days of age respectively. Both had right arm tenderness on palpation and passive movement. Roentgenograms of their right shoulder joints showed irregular radiolucency of the proximal margin of right humerus head. In both cases, electromyography revealed various degrees of significant denervation pattern for the C5-C7 innervated muscles. Pus culture from right shoulder joints grew Streptococcus viridans and Staphylococcus aureus, respectively. After antibiotic therapy and arthrotomy with drainage, weakness improved gradually following continuous rehabilitation. Follow-up at six months of age showed almost complete recovery of right upper extremity function in one patient, but mild residual weakness in the other. Follow-up electromyography studies showed continued improvement. The possible mechanism of this rare occurrence is discussed.

Subependymal giant cell astrocytoma with tuberous sclerosis--case report

Tuberous sclerosis is a rare disease of autosomal dominant inheritance and may affect any organ, and less than 2% have a subependymal giant cell astrocytoma. In the present report, a 6-year-old girl with clinical features of tuberous sclerosis had an intraventricular tumor. CT scan and MRI of brain showed a tumor in the lateral ventricles extended into the Foramina of Monro and third ventricle causing severe hydrocephalus. She underwent left frontal craniotomy with partial removal of the tumor. The pathology was subependymal giant cell astrocytoma. Patient's neurological condition improved postoperatively and postoperative CT scan showed no hydrocephalus. Clinical and radiological follow-up of patients with tuberous sclerosis who had subependymal nodules in early childhood is important due to its possibility of subsequent transformation into intraventricular tumor.

Axotomy results in delayed death and apoptosis of retinal ganglion cells in adult rats

Using quantitative anatomical techniques, we show that after intraorbital optic nerve transection in adult rats, virtually all retinal ganglion cells (RGCs) survive for 5 d and then die abruptly in large numbers, reducing the RGC population to approximately 50% of normal by day 7 and to less than 10% on day 14. During this period of rapid cell loss, some RGCs show cytochemical alterations indicative of apoptosis ("programmed cell death"), a change not previously categorized after axotomy in adult mammals. With intracranial lesions 8-9 mm from the eye, the onset of cell death is delayed until day 8 and is greater with cut than crush. The demonstration that axotomy results in apoptosis, the long interval between axonal injury and RGC death, and the different time of onset of the massive RGC loss with optic nerve lesions near or far from the eye suggest that axonal interruption triggers a cascade of molecular events whose outcome may be critically dependent on the availability of neuronal trophic support from endogenous or exogenous sources. The role of such molecules in RGC survival and the reversible nature of these injury-induced changes is underscored by the temporary rescue of most RGCs by a single intravitreal injection of brain-derived neurotrophic factor during the first 5 d after intraorbital optic nerve injury (Mansour-Robaey et al., 1994). The delayed pattern of RGC loss observed in the present experiments likely explains such a critical period for effective neurotrophin administration.

Bromocriptine treatment of postoperative prolactinoma patients

BACKGROUND

Prolactinoma is the leading cause of pituitary adenoma. It causes amenorrhea in women and impotence in men. Surgical and bromocriptine treatment are the mainstays of therapy in most of the patients with this disease. Determining the outcome for postoperative hyperprolactinemia patients who received bromocriptine treatment was the main purpose of this study.

METHODS

Thirty-two patients who received operation for prolactinoma have been investigated. Twenty of them had received bromocriptine treatment before conception, 14 were diagnosed as having macroadenoma and all of them had post-operative hyperprolactinemia.

RESULTS

Five patients needed bromocriptine treatment of more than 12.5mg/day to decrease the serum prolactin level. Three patients received radiotherapy postoperatively. Other patients were bromocriptine sensitive. Eight of them had menses restored, and of these, five became pregnant.

CONCLUSIONS

Operation can successfully treat most of the patients with microadenoma. If there has postoperative hyperprolactinemia, bromocriptine treatment should be the first choice before radiotherapy.

Effects of ocular injury and administration of brain-derived neurotrophic factor on survival and regrowth of axotomized retinal ganglion cells

Optic nerve transection in adult rats results in the death of approximately 50% of the axotomized retinal ganglion cells (RGCs) by 1 week and nearly 90% by 2 weeks after injury. The capacity of brain-derived neurotrophic factor (BDNF) to prevent this early, severe loss of RGCs was investigated in vivo by intravitreal injections of BDNF [5 micrograms in 5 microliters of bovine serum albumin/phosphate-buffered saline (BSA/PBS)] or vehicle (5 microliters of BSA/PBS). Using quantitative anatomical techniques, we show that (i) all RGCs survived 1 week after a single injection of BDNF at the time of axotomy. (ii) RGC densities decreased in the BDNF-treated retinas by 2 weeks but remained significantly greater than in the untreated controls. (iii) An enhanced RGC survival was obtained with single injections of BDNF from 6 days before to 5 days after axotomy. (iv) Repeated injections resulted in greater numbers of surviving RGCs, an effect that declined to undetectable levels by 6 weeks. (v) There were indications for an endogenous local source of trophic support whose expression was triggered by ocular injury, particularly to the anterior part of the eye. (vi) With multiple BDNF injections, there was profuse axonal sprouting around the optic disc. This remarkable intraretinal growth was not, however, reflected in increased RGC innervation of the peripheral nerve grafts, which are known to facilitate regeneration when used as optic nerve substitutes.

[The performances of attention deficit/hyperactivity disorder on neuropsychological tests of children]

The purpose of this study was to investigate the Attention Deficit/Hyperactivity Disorder (ADHD) by neuropsychological tests of children. There were two groups of subjects; one group was 23 ADHD children, the other group was 33 normal children. All of the subjects were 5 to 8 years old (mean = 7.05). The social economic status differences were nonsignificant between the two groups (chi-square = 0.52, p > 0.05). The instruments were WISC-R, Tests of Psycholinguistic Abilities, Diagnostic Arithmetic Test, and Reitan-Indiana Neuropsychological test for yound children. The findings were: (1) For all IQs (verbal, performance, full), the ADHD group was significantly lower than the normal group, and there were 8 (34.8%) ADHD children who were mental retards, 3 (13.0%) ADHD children were borderline mental retards, and there was just one (3.0%) normal child who was a borderline mental retard. (2) For academic abilities (Tests of Psycholinguistic Abilities, and Diagnostic Arithmetic Tests), the ADHD group was significantly (p < 0.05) lower than the normal group, and the higher the grade, the larger the difference. (3) For neuropsychological tests, if cut-off points of performance level (0, 1, 2, 3) were percentile 5, 10, and 25 for all of the subjects, then there 12 variable criteria were lower than the Reitan's, 3 variable criteria were higher than the Reitan's, 29 variable criteria were similar with Reitan's, and 8 variables were indiscriminate between individuals. (4) The motor functions and higher cognitive abilities of the ADHD group were worse than those of the normal group.

Molecular and cytogenetic analyses of autism in Taiwan

Karyotypic and DNA analyses were both performed on 104 autistic children referred from Taichung Autism Education Academy and Tainan Autism Association in Taiwan. The frequency of fragile sites of the autistic patients did not differ significantly from that of the normal individuals. Of the 12 autistic children with chromosomal abnormalities, 8 had the fragile X, 2 had Down syndrome, and the remaining had other aneuploid constitutions. The results of this study illustrate the contribution of chromosomal abnormalities or variants to the pathogenesis of infantile autism.

Benign seizures associated with mild diarrhea: clinical analysis of 20 cases

Even without electrolyte imbalance, dehydration and fever, seizures are found occasionally in the cases of mild diarrhea. Such patients have shown favorable outcome during long-term follow-up. Twenty cases (10 boys and 10 girls) of benign seizure with mild diarrhea have been diagnosed at the Pediatric Department of Cathay General Hospital from January 1987 to March 1991. Ages-of-onset ranged from 3 months to 43 months (mean 19 months). Most cases were found between December and March (16 cases, 80%). Most seizure episodes were from 2 to 5 times (10 cases, 50%); the durations of seizures were mostly within a 5-minute period (16 cases, 80%). All seizures were generalized and symmetric, including tonic-clonic (13 cases, 65%), tonic (5 cases, 25%), and clonic (2 cases, 10%). Six out of 11 cases (54.5%) showed Rotazyme (Latex agglutination) positive. After six month to four year follow up, no patient had suffered any type of epilepsy, and psychomotor development was normal in all. Further discussion of clinical features is provided.

A retinoblastoma-binding protein related to a negative regulator of Ras in yeast

The growth suppression function of the retinoblastoma protein (Rb) is though to be mediated by Rb binding to cellular proteins. p48 is one of the major proteins that binds to a putative functional domain at the carboxy terminus of the Rb protein. Here we report the isolation of a full-length complementary DNA (RbAp48) encoding p48. Complex formation between p48 and Rb occurs in vitro and in vivo, and apparently involves direct interaction between the proteins. Like Rb, p48 is a ubiquitously expressed nuclear protein. RbAp48 share sequence homology with MSI1, a negative regulator of the Ras-cyclic AMP pathway in the yeast Saccharomyces cerevisiae. Furthermore, like MSI1, human RbAp48 suppresses the heat-shock sensitivity of the yeast ira1 strains and RAS2Val19 strains. Interaction with p48 may be one of the mechanisms for suppression of growth mediated by Rb.

[The effect of intracranial pressure caused by airway suction in hypertensive intracerebral hemorrhagic comatose patients]

Ten hypertensive intracerebral hemorrhagic comatose patients in the Neurosurgical Intensive Care Unit were involved in this study. The ten were within the range of 5 to 8 by Glasgow Coma Scale, and all had undergone tracheostomy. During suction of the airway for 20 seconds in 4 areas (trachea, bronchus, nasal and oral cavities), the data of intracranial pressure (ICP), arterial blood pressure, pulse rate (PR) and respiration rate (RR) were recorded. Results were analyzed for ICP, mean arterial blood pressure (MABP), PR, RR, and cerebral perfusion pressure (CPP) at the 5th, 10th, 15th and 20th seconds in the above-mentioned areas. The ICP was found to be significantly increased, and above the 20 mmHg mark, during suction of the bronchus or nasal cavity for 5 seconds. The MABP also showed significant increase, to above the 110 mmHg mark during 5-second suction of the trachea or nasal cavity or during suction of the bronchus or oral cavity for 10 seconds. However, during the suction of the four airway areas, PR and RR were less influenced and the CPP was not decreased or significantly changed. The conclusion of this study was that suction in the areas of trachea, bronchus and nasal cavity, should not exceed 5 to 10 seconds; in the oral cavity, it may be done within 10 to 15 seconds and at each procedure of airway suction. If it is not possible to clean the sputum or secretion in one procedure, the patient should be allowed to rest for about one minute or become stabilized as determined by watching the monitors of ICP, BP, PR, and RR.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence from mutation spectra that the UV hypermutability of xeroderma pigmentosum variant cells reflects abnormal, error-prone replication on a template containing photoproducts

Xeroderma pigmentosum (XP) variant patients are genetically predisposed to sunlight-induced skin cancer. Fibroblasts derived from these patients are extremely sensitive to the mutagenic effect of UV radiation and are abnormally slow in replicating DNA containing UV-induced photoproducts. However, unlike cells from the majority of XP patients, XP variant cells have a normal or nearly normal rate of nucleotide excision repair of such damage. To determine whether their UV hypermutability reflected a slower rate of excision of photoproducts specifically during early S phase when the target gene for mutations, i.e., the hypoxanthine (guanine) phosphoribosyltransferase gene (HPRT), is replicated, we synchronized diploid populations of normal and XP variant fibroblasts, irradiated them in early S phase, and compared the rate of loss of cyclobutane pyrimidine dimers and 6-4 pyrimidine-pyrimidones from DNA during S phase. There was no difference. Both removed 94% of the 6-4 pyrimidine-pyrimidones within 8 h and 40% of the dimers within 11 h. There was also no difference between the two cell lines in the rate of repair during G1 phase. To determine whether the hypermutability resulted from abnormal error-prone replication of DNA containing photoproducts, we determined the spectra of mutations induced in the coding region of the HPRT gene of XP variant cells irradiated in early S and G1 phases and compared with those found in normal cells. The majority of the mutations in both types of cells were base substitutions, but the two types of cells differed significantly from each other in the kinds of substitutions, but the two types differed significantly from each other in the kinds of substitutions observed either in mutants from S phase (P < 0.01) or from G1 phase (P = 0.03). In the variant cells, the substitutions were mainly transversions (58% in S, 73% in G1). In the normal cells irradiated in S, the majority of the substitutions were G.C --> A.T, and most involved CC photoproducts in the transcribed strand. In the variant cells irradiated in S, substitutions involving cytosine in the transcribed strand were G.C --> T.A transversions exclusively. G.C --> A.T transitions made up a much smaller fraction of the substitutions than in normal cells (P < 0.02), and all of them involved photoproducts located in the nontranscribed strand. The data strongly suggest that XP variant cells are much less likely than normal cells to incorporate either dAMP or dGMP opposite the pyrimidines involved in photoproducts. This would account for their significantly higher frequency of mutants and might explain their abnormal delay in replicating a UV-damaged template.

[Effect of implantation of an Ommaya reservoir on prognosis for cryptococcal meningitis]

Cryptococcal meningitis has a high mortality rate of central nervous infection. The patients usually die of the disease itself, or complications from increased intracranial pressure. Early diagnosis and treatment, including surgical drainage, will improve the results. In this series, twenty-one patients with high intracranial pressure (ICP > 300 mmH2 O) are presented. Fourteen received implantation of Ommaya reservoir to aspirate cerebrospinal fluid (CSF) for relief of symptoms of ICP. Meanwhile 4 of these 14 patients also received intraventricular injection of amphotericin B because of poor response to systemic drugs. Another seven patient received systemic drug therapy only. Survival during therapy occurred in 11 of 14 patients in the surgical group, compared with only 1 of 7 patients treated by drug therapy alone (P = 0.019). In the 14 patients who received implantation of an Ommaya reservoir, there was one complication of CSF leakage when the reservoir ruptured because of repeated aspiration. For patients with cryptococcal meningitis with high ICP, early implantation of an Ommaya reservoir will improve the survival rate.