Amino acids in extracellular fluid in vasogenic brain edema

We have investigated if changes in brain dialysate, reflecting alterations in brain extracellular composition, can be detected during the development of vasogenic brain edema. The blood-brain barrier was opened by intracarotid infusion of 5 or 10 mg protamine sulphate. The rats were killed two hours after opening of the BBB when the brains were macroscopically edematous, after 10 mg but not 5 mg protamine sulphate. No significant alterations in the amino acid concentration in the dialysate were observed after the lower dose. 40 min after infusion of 10 mg protamine, the level of glutamate was significantly increased in the dialysate followed by that of aspartate, glycine, phosphoethanolamine and taurine 10 min later and a further delayed increase in GABA. We conclude that the development of vasogenic brain edema is associated with significant increases in extracellular concentration of excitatory amino acids, of taurine, and of phosphoethanolamine and GABA.

Stomatococcus mucilaginosus septicemia in two bone marrow transplanted patients

A 44-year-old man with chronic myeloid leukemia and a 10-year-old boy with adrenoleukodystrophy, both admitted for bone marrow transplantation in December 1992, developed clinical signs of septicemia within 2 weeks after transplantation. Three strains of Stomatococcus mucilaginosus were isolated from blood cultures. These were among the first cases of S. mucilaginosus infection diagnosed at our Laboratory and the first reported from Scandinavia. S. mucilaginosus is part of the endogenous oral flora. Both patients had signs of oral mucositis. All 3 strains were isolated earlier with the Laboratory's present blood culture system, compared with the one in use before spring 1992.

Concentrations of amino acids in extracellular fluid after opening of the blood-brain barrier by intracarotid infusion of protamine sulfate

This article evaluates the influence of an opening of the blood-brain barrier (BBB) on compounds in brain extracellular fluid. The concentrations of amino acids and some other primary amines were determined in dialysates sampled from the right parietal cortex of rats before and after an intracarotid infusion of protamine sulfate. Extravasated plasma proteins were visualized by Evans blue/albumin and immunohistochemistry. CSF albumin--an indicator of blood-CSF barrier opening--was quantified with immunoelectrophoresis. The brains were macroscopically edematous after 10 mg but not after 5 mg of protamine sulfate. The higher dose led to a 50% death rate. The concentrations of amino acids did not change 10 min after the BBB opening. No significant alterations in the amino acid concentrations were observed after the lower dose. The concentrations of glutamate, aspartate, GABA, glycine, taurine, and phosphoethanolamine increased significantly within 50-80 min after the infusion of 10 mg of protamine sulfate. CSF albumin levels were significantly increased 1 h after infusion. We conclude that a dysfunction of the BBB, of a degree known to induce brain edema (10 mg of protamine sulfate), significantly increases the extracellular concentration of excitatory amino acids, GABA, taurine, and phosphoethanolamine in the extracellular space.

Thoughts on levels of microbial cleanliness and on validating disinfection procedures

Efforts of the European Committee of Standardization (CEN) and the International Organization for Standardization (ISO) to harmonize production standards for medical devices have brought to the fore the need to standardize definitions and names for different levels of microbial contamination as well as validation procedures for microbial inactivation. Spaulding's categories of medical devices (critical, semi-critical and noncritical items) suggest that different levels of cleanliness can be accepted. Current terminology is imprecise and does not provide the necessary information to the user. A more appropriate one is needed. So are methods to validate microbial inactivation processes to lower levels of cleanliness than sterility. In Sweden, a couple of validation studies have been performed on bacterial inactivation in automatic washing machines which disinfect through a final hot water or steam rinse. However, more studies need to be done, especially on viral inactivation.

Biochemical correlates to cortical dysplasia, gliosis, and astrocytoma infiltration in human epileptogenic cortex

The study provides detailed biochemical correlates to the common histopathological diagnoses in epilepsy. A dot immunobinding procedure was used for quantification of NSE, GFA, S-100, NCAM, NF 68 and NF 200. The material consisted of samples from 48 patients either selected for surgical treatment of partial epilepsy or for disorders not related to epilepsy. The histopathological diagnosis of the epileptic cases was: MCD (mild cortical dysplasia, microdysgenesis), gliosis, astrocytoma, ganglioglioma, oligodendroglioma and single cases. The concentration in non-epileptic white matter, in per cent of that in grey matter was: NSE, 85; GFA, 175; S-100, 117; NCAM, 43; NF 68,227 and NF 200, 173. The concentration of NSE as well as of GFA was close to normal in the specimens of the MCD and gliosis groups and of one subgroup of the astrocytomas. There was a striking inverse relationship of the GFA vs the NSE concentrations in the whole material. The concentrations of S-100 showed no such inverse relationship to NSE levels. In all the epileptic groups, total NCAM was lower than 50% of that of the non-epileptic group. The mean NF 68 and NF 200 concentration in the gliosis and astrocytoma groups was 75% of that of the non-epileptic group while the corresponding value for the MCD group was 50%. There was a positive correlation of immunochemically determined GFA and the histopathological gliosis score in the samples of epileptogenic cortex. There was no correlation between the concentration of GFA in the samples and the duration of epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Co-variation of free amino acids in human epileptogenic cortex

The concentration of free amino acids was measured in 41 surgically removed samples of human epileptogenic brain and in 7 specimens of non-epileptic brain tissue, removed during surgery for meningiomas, etc. The material was subdivided according to the neuropathological diagnosis: mild cortical dysplasia (MCD), gliosis astrocytoma infiltration and a histologically heterogeneous group. The non-tumoral epileptogenic samples had five times higher than normal concentration of ethanolamine and 50% elevated concentration of glycine. The concentration of other neurotransmitter amino acids did not differ markedly between epileptogenic and non-epileptic samples. The concentration of neurotransmitter amino acids showed a strong correlation with the enzyme neuron specific enolase (NSE) and were low in most samples with astrocytoma infiltration. On the other hand, tyrosine and leucine had higher concentrations in samples with lower NSE concentration. Factor analysis of the amino acids revealed four groups of covarying compounds in the brain samples, first, a neurotransmitter group, including aspartate, glutamate, GABA and phosphoethanolamine. Another group contained ethanolamine, glutamine, glycine and taurine. Factor analysis on corresponding extracellular amino acids showed two groups, the first being a "neurotransmitter" group, containing serine, taurine phosphoethanolamine and ethanolamine in addition to aspartate and glutamate. The other group consisted of asparagine, glycine, alanine, tyrosine, valine, phenylalanine, isoleucine and leucine.

Colonization with coagulase-negative staphylococci in two neonatal units

Episodes of septicaemia due to coagulase-negative staphylococci (CNS) were more frequent in a level III than in a level II neonatal unit in Stockholm, Sweden. Colonization with CNS during the first 2 weeks of life was investigated in 10 infants from each unit. As the use of antibiotics differed between the two units, the aim was to correlate colonization and antimicrobial resistance patterns to antibiotic usage. Antimicrobial susceptibility of CNS to isoxazolylpenicillins, co-trimoxazole, erythromycin, clindamycin, chloramphenicol and gentamicin was determined. Selected isolates were typed with restriction endonuclease analysis of plasmid DNA and of genomic DNA. Infants were frequently colonized with multiple strains and species of CNS, and transmission of strains from patient to patient occurred within the unit. Qualitative and quantitative differences in antibiotic use were not correlated with colonization. The prevalence of resistant isolates, mostly of Staphylococcus haemolyticus, was higher in the level II unit with lower use of antibiotics. Staphylococcus epidermidis, which is generally more virulent, prevailed in the level III unit, where there were more severely ill children and invasive procedures were more frequently performed.

The role of hospital infection control in the quality system of hospitals

Like other highly specialized fields, quality systems have their own vocabulary which we must be familiar with; it has been internationally standardized. This standard should be adhered to in order to avoid unnecessary ambiguities and confusion, and to facilitate exchange of information between disciplines. We, in the infection control field, are quality pioneers in hospitals. We have, within our discipline, created quality systems and practised quality surveillance for decades. This must be recognized. Medical quality audits intended for comparisons between hospitals, services and wards require measurable quality criteria and comparable measures for the presence of all relevant patient-related risk factors. To specify quality within our field we need much more detailed information on the effect and cost of infection control practices, as well as the costs of the infections we intend to control. To progress one step further, patients or their representatives, politicians, need to express what monetary value should be put on health, namely freedom from infection and its consequences.

Fatal systemic poisoning after skin exposure to monochloroacetic acid

Little information is available on the toxicity of monochloroacetic acid. We report the case of a 38 year-old man who was splashed with an 80% monochloroacetic acid solution on 25-30% of his body surface. In addition to epidermal and superficial dermal burns, features of systemic poisoning occurred within a few hours including disorientation, agitation, cardiac failure and coma. He later developed severe metabolic acidosis, rhabdomyolysis, renal insufficiency and cerebral edema, and died due to uncal herniation on d 8. The 4 h post exposure plasma monochloroacetic acid concentration was 33 mg/L confirming skin absorption. In addition to its corrosive action, monochloroacetic acid probably blocks the tricarboxylic acid cycle (Kreb's cycle) and may also react with sulfhydryl groups in enzymes, causing severe tissue damage in energy-rich organs.

Hospital-associated infections in obstetrics and gynecology. Effects of surveillance

STUDY OBJECTIVE

To determine whether continuous surveillance of hospital-associated infections with regular feed-back to the staff reduces the infection rate in obstetrics and gynecology.

DESIGN

Two infection control nurses surveyed all patients over a 2-year period for infections and potential risk factors. After an initial 9-month period (period A), quarterly information to all doctors and nurses was introduced for the rest of the study (period B).

SETTING

A department of obstetrics and gynecology at a Swedish university hospital.

PATIENTS

All patients undergoing surgery, excluding vacuum aspiration abortions and dilatation and curettage.

MAIN RESULTS

2,334 patients were surveyed. In period A, 14.2% of all operations were followed by an infection, compared with 9.5% in period B (p less than 0.001). For purulent wound infections and for endometritis, a significantly reduced rate was noted from period A to B. Several risk factors for infection were significantly more common in period B than in period A. Cesarean sections and hysterectomies were the most common operations also having among the highest infection rates. For both of these operations, infection rates were significantly reduced from period A to period B (from 15.1% to 9.0% and from 15.7% to 10.7%, respectively). The average length of hospitalization was 6 days longer for an infected than for an uninfected patient.

CONCLUSIONS

Surveillance of hospital-associated infections including regular feed-back to the staff was accompanied by a significant reduction in infection rates. A quality surveillance program for departments of obstetrics and gynecology therefore seems to benefit from including such surveillance. Surveillance could possibly be limited to only a few common operations with high infection rates.

Microdialysis sampling of the neuronal environment in basic and clinical research

Microdialysis is a technique for sampling extracellular fluid (ECF) which has been employed in brain research for about 10 years, and is now in experimental and clinical use in a number of biomedical disciplines. We report on microdialysis of neuroactive amino acids in the central nervous system (CNS) and discuss some technical problems of microdialysis, such as tissue reactions, calibration and the difficulties involved, as well as strategies for determination of the true extracellular concentration of various compounds. Possible mechanisms of nerve cell death in ischaemia and hypoglycaemia are among the factors that have been elucidated using data obtained by microdialysis. The neuronal environment overflows with excitatory amino acids both in brain ischaemia and in hypoglycaemia.

New technology for sterilization and disinfection

Sterilization with low temperature steam and formaldehyde is a well-known process in many European countries, but little known in the United States. It sterilizes reliably and reproducibly at temperatures greater than or equal to 65 degrees C. With a well-designed cycle, it leaves residues of formaldehyde on sterilized items below 5 micrograms/cm2, measured on a standard filter paper. Formaldehyde levels in air near the autoclave are well below official exposure limits, if at all measurable. Occurrence of late growers in bioindicators, and penetration of the sterilizing media into long narrow lumina, should be validated for new processes. Automated cleaning and disinfection in closed washer-disinfectors and flushing disinfectors are likewise processes relatively little known in the United States. Disinfection is achieved by a final rinse with hot water or steam. Washer-disinfectors are used for surgical instruments, nondisposable anesthesia and other equipment, flushing disinfectors for nondisposable bedpans, wash-bowls, urinals, and similar equipment. They clean well, washer-disinfectors excellently so, and disinfect reliably. With the use of such equipment in wards, surgical departments, and other areas, reliance on chemical germicides can be dramatically reduced and disposables can be replaced by disinfectable nondisposables.

Quantitative sensory testing before and after regional guanethidine block in patients with neuralgia in the hand

Using reference values from healthy volunteers, thermal and vibration-induced pain thresholds and the sensibility for warm and cold were studied in 18 patients with neuralgia in one hand following a traumatic injury or surgery. All patients had spontaneous pain and allodynia to vibration. They were treated with intravenous regional guanethidine block (RGB). Quantitative sensory testing was performed on both hands before and 1-3 days after treatment. Eleven patients benefitted considerably from the block, with pain relief for 2 weeks or more. Ten of these 11 patients had mild nerve injuries caused by compressive trauma to the nerve. Before RGB they showed a moderate loss in temperature discrimination capacity; their heat pain thresholds were reduced and they exhibited allodynia to cold and vibration on the injured side. After RGB, the pain thresholds were normalised both to thermal and vibratory stimuli. These patients were classified as having sympathetically maintained pain (SMP). Seven patients reported no or only minor pain-relieving effect of RGB lasting 1-5 days. Severe nerve injuries were most frequent in this group of patients. On the injured side, before RGB, their ability to discriminate between warm and cold was markedly impaired, thermal pain thresholds were normal, and they showed allodynia to vibration. After RGB, there was no change in thermal pain thresholds and the allodynia to vibration persisted. These patients were classified as having sympathetically independent pain (SIP). The results indicate that quantitative thermal sensory tests, together with clinical evaluation of the nerve trauma, can help to predict which patients will have long-lasting pain alleviation after RGB treatment.

Infection control policies and guidelines--Scandinavian experience

In the Scandinavian countries few regulations govern hospital infection control. In Sweden a common procedure manual is used nationwide, consisting of guidelines covering a wide range of nursing and medical procedures performed by the nursing staff. It is revised every fifth year. A recent enquiry to over 150 wards in some 100 hospitals demonstrated that the manual is widely accepted and used. In the other Scandinavian countries, guidelines and policies on a variety of infection control topics have been published.

Amino acids in the neuronal microenvironment of focal human epileptic lesions

Extracellular fluid was topically sampled with a dialysis probe during electrocorticography from the exposed cerebral cortex in 23 patients undergoing epilepsy surgery. Sampling was done in parallel from epileptiform regions and from non-epileptic areas. The former were classified according to the histopathology, into neoplastic, non-tumoral or 'special cases'. The epileptiform regions had significantly higher extracellular concentrations of alanine, glycine and phosphoethanolamine in the majority of the cases. The excised epileptic lesions were analyzed to provide the corresponding intracellular concentrations of amino acids. Several of the non-tumoral group showed high concentrations of GABA, ethanolamine and alanine. The intra- to extracellular concentration ratio for amino acids was low for phosphoethanolamine, glycine, serine and glutamine in most of the samples of epileptiform cortex, while the intracellular accumulative ability for ethanolamine apparently was stronger in epileptiform than in normal cortex.

On the prevention of caries and periodontal disease. Results of a 15-year longitudinal study in adults

In 1971-72, a total of 375 adult subjects were recruited for a clinical trial aimed at assessing the effect of a preventive program, based on plaque control and topical application of fluoride, on the incidence of caries and periodontal disease. After a baseline examination, the volunteers were subjected to scaling, root planning and conventional caries therapy. During the course of the subsequent 6 years, they were recalled for preventive measures once every 2-3 months. After the 6-year follow-up examination, however, it was decided to extend the interval between the preventive sessions. Thus, during the next 9-year period, about 95% of the participants returned for preventive measures only 1 to 2 times per year. A small subgroup of about 15 subjects, who, during the initial 6 years had developed new caries lesions or had exhibited additional periodontal attachment loss, however, were also during the following 9 years recalled 3-6 times per year for oral hygiene control and preventive therapy. The re-examination performed in 1987 disclosed that the 317 subjects, who participated during the entire 15-year period, had a low incidence of caries and almost no further loss of periodontal tissue support. It was suggested that improved self performed oral hygiene, daily use of fluoridated dentifrice and regularly repeated professional tooth cleaning effectively prevented recurrence of dental disease.

Reduction of contamination at total hip replacement by special working clothes

We assessed wound, air and operative field contamination at 50 total hip operations, performed in a zonal ventilation system. Theatre staff wore either a specially designed polypropylene non-woven coverall or conventional cotton shirt and trousers. The surgeons wore partially impermeable operating gowns. The polypropylene coverall was associated with significantly lower air and wound counts. The coverall was warmer than cotton but judged to be acceptable. The combined use of zonal ventilation and the coverall achieved ultra-clean air conditions.

Effect of methylprednisolone on motor function and spinal cord blood flow after spinal cord compression in rats

The effect of methylprednisolone (MP) on neurologic recovery and spinal cord blood flow (SCBF) was investigated up to 4 days after a spinal cord compression injury in rats. The injury was produced at midthoracic level by applying a load of 35 g on a 2.2 x 5.0 mm compression plate for 5 min, which resulted in transient paraparesis. MP was given as a bolus dose of 30 mg/kg i.v. 60 min after injury (n = 20) and controls were given saline (n = 10). The motor performance was assessed daily as the capacity angle on the inclined plane and SCBF was measured by 14C-iodoantipyrine autoradiography on Days 1 or 4. On Day 1 the capacity angle was reduced from about 63 degrees preoperatively to 33 +/- 2 degrees (mean +/- SEM) in the control group and to 50 +/- 1 degrees in the group treated with MP (p less than 0.05). Thereafter there was a slight improvement in both groups, but the difference persisted throughout the observation period. On Day 4 both gray and white matter SCBF was better preserved in MP-treated animals than in the control group (59 +/- 4 versus 49 +/- 3 ml/min/100 g tissue for gray matter and 13.6 +/- 0.6 versus 10.7 +/- 0.8 ml/min/100 g tissue for white matter). Posttraumatic treatment with MP, thus, improved both the neurologic recovery during the first 4 days and SCBF as measured on Day 4. It is speculated that the effect of MP is at least partly exerted on the vascular bed.

Relation between spinal cord blood flow and functional recovery after blocking weight-induced spinal cord injury in rats

Spinal cord blood flow (SCBF) and motor performance on the inclined plane were measured up to 9 days after a reversible spinal cord compression injury in 49 Sprague-Dawley rats. A load of 35 g on 11 mm2 of the thoracic spinal cord for 5 minutes caused transient paraparesis with a decrease in the capacity angle on the inclined plane from 62 +/- 1 degree (mean +/- SEM) before injury to 33 +/- 1 degree on Day 1, 45 +/- 2 degrees on Day 4, d and 54 +/- 3 degrees on Day 9. SCBF was measured by the [14C]iodoantipyrine method, and in gray matter there was a decrease from 78.4 +/- 2.3 ml/min/100 g of tissue in uninjured animals to 33.7 +/- 1.5 ml/min/100 g of tissue on Day 1 after injury, increasing to 50.1 +/- 2.0 on Day 4 and to 70.5 +/- 2.7 ml/min/100 g of tissue on Day 9. At the corresponding times, the SCBF values in white matter were 14.5 +/- 0.5, 6.7 +/- 0.5, 10.2 +/- 0.6, and 13.4 +/- 0.6 ml/min/100 g of tissue, respectively. The animals in another group were loaded with 25 g for 5 minutes and on Day 1 exhibited a capacity angle of 43 +/- 2 degrees while the SCBF values for gray and white matter were 55.1 +/- 2.0 and 11.1 +/- 0.4 ml/min/100 g of tissue, respectively; thus, the results in this group were similar to the values on Day 4 in the animals loaded with 35 g.(ABSTRACT TRUNCATED AT 250 WORDS)

The contribution from the choroid plexus and the periventricular CNS to amino acids and proteins in the human CSF

During neurosurgery the freshly secreted extracellular fluid (ECF) from the choroid plexus was sampled with small pieces of application paper in three patients with intractable epilepsy. The samples were analyzed for free amino acids and for soluble proteins. The results were compared with corresponding data on extracellular fluid from the brain surface obtained with dialysis-perfusion as well as with the cerebrospinal fluid (CSF) acquired by lumbar punction. The dialysis data were calibrated against the paper results. The choroid plexus secretion had a high concentration of transthyretin as well as of an unidentified protein with an isoelectric point of 7.4. The cortical ECF exhibited high concentrations of tau-globulin and gamma-trace protein. Among the amino acids, glutamine had lower concentration in the choroid plexus secretion and higher concentrations in the ECF of the brain compared to the CSF. The amino acid derivative ethanolamine exhibited a similar pattern. This was interpreted to demonstrate that these compounds enter the CSF from the brain tissue. In contrast, alanine, serine, and taurine had a lower concentration in the CSF than in the plexus secretion which suggests that they are removed from the CSF by brain tissue.

Neuropathological changes and neurological function after spinal cord compression in the rat

As part of a series of experimental investigations of the effects of various pharmacological agents on the outcome of compressive spinal cord trauma in the rat, the time course of the cell changes in the cord at the site of and distal to the compression was studied at the light microscopic level. The degree of compression used with the present model results in a transient paraparesis that recovers almost completely over a period of 3 weeks as judged by the inclined plane technique. The most significant morphological findings were as follows. Initially (1 and 24 h after the impact) there was pronounced swelling and hemorrhage at the compression site, chiefly in the gray matter of the cord. On day 4 there was severe necrosis in the same region, with numerous macrophages and leukocytes. Rats killed after 21 days showed either minor residual signs of necrosis or essentially normal tissue architecture. Surprisingly, necrosis with delayed onset also developed in the dorsal columns, involving the pyramidal tracts. This necrosis was detected in animals killed after 9 and 21 days but not in those observed after 4 days or earlier. The longitudinal tracts of the white matter showed reduced staining in paraffin sections of the compression site. Epon sections revealed splits in the myelin sheaths and enlarged periaxonal spaces as early as 1 h after the impact. The alterations in the longitudinal tracts persisted throughout the 21-day observation period and extended down to L2-L4. There was gradual functional recovery, documented by the inclined plane test. Preinjury values were almost reached on day 21, although the cord still showed some morphological damage. In individual animals, no relation was found between degree of function as tested by inclined plane and extent of morphologic injury. Additional functional and morphological methods obviously are needed in future investigations of the effects of treatments on the outcome of compressive spinal cord injury.

Blocking weight-induced spinal cord injury in rats: effects of TRH or naloxone on motor function recovery and spinal cord blood flow

The ability of thyrotropin releasing hormone (TRH) or naloxone to reduce the motor function deficit and to improve the spinal cord blood flow (SCBF) was investigated in a rat spinal cord compression injury model. Spinal cord injury was induced by compression for 5 min with a load of 35 g on a 2.2 x 5.0 mm sized compression plate causing a transient paraparesis. One group of animals was given TRH, one group naloxone and one group saline alone. Each drug was administered intravenously as a bolus dose of 2 mg/kg 60 min after injury followed by a continuous infusion of 2 mg/kg/h for 4 h. The motor performance was assessed daily on the inclined plane until Day 4, when SCBF was measured with the 14C-iodoantipyrine autoradiographic method. It was found that neither TRH nor naloxone had promoted motor function recovery or affected SCBF 4 days after spinal cord injury.

Spinal cord injury in rats: inability of nimodipine or anti-neutrophil serum to improve spinal cord blood flow or neurologic status

The role of a calcium-mediated increase in vascular resistance and of vascular damage caused by polymorphonuclear leukocytes (PMNLs) in the development of neurologic deficit and disturbance of spinal cord circulation following spinal cord compression was studied in the rat. Spinal cord injury was induced by 5 min of compression with a load of 35 g on a 2.2 X 5.0 mm compression plate. This caused transient paraparesis. The rats received either the calcium receptor antagonist nimodipine or an anti-rat neutrophil serum (ANS). Nimodipine was infused i.v. for 4 h in an amount of 1.5 micrograms/kg/min starting 60 min after trauma. The number of circulating PMNLs was depleted by intraperitoneal injection of an ANS raised in sheep given 12 h before trauma. This caused a reduction to about 2% of the pre-ANS value. Controls received saline or normal sheep serum. The motor performance was assessed daily on the inclined plane. On day one, the day after injury, the capacity angle had decreased from about 63 degrees preoperatively to close to 32 degrees in the experimental groups. There was then a slow improvement in both the control and experimental groups and on day 4 the capacity angle was close to 43 degrees in all 3 groups. Spinal cord blood flow, as measured with the 14C-iodoantipyrine autoradiography method, was similar in all groups on day 4. As neither the neurologic dysfunction nor the spinal cord blood flow was affected by post-trauma treatment with nimodipine or pretreatment with ANS, the possibility that calcium-mediated vasoconstriction or PMNLs play a role in the development of posttraumatic neurologic disability was not supported by this study.

Spinal cord blood flow measured by 14C-iodoantipyrine autoradiography during and after graded spinal cord compression in rats

The relations between degree of thoracic spinal cord compression causing myelographic block, reversible paraparesis, and extinction of the sensory evoked potential on one hand, and spinal cord blood flow on the other, were investigated. This was done in rats using the blocking weight-technique and 14C-iodoantipyrine autoradiography. A load of 9 g caused myelographic block. Five minutes of compression with that load caused a reduction of spinal cord blood flow to about 25%, but 5 and 60 minutes after the compression spinal cord blood flow was restored to 60% of the pretrauma value. A load of 35 g for 5 minutes caused transient paraparesis. Recovery to about 30% was observed 5 and 60 minutes thereafter. During compression at a load of 55 g, which caused almost total extinction of sensory evoked potential and irreversible paraplegia, spinal cord blood flow under the load ceased. The results indicate that myelographic block occurs at a load which does not cause irreversible paraparesis and that a load which permits sensory evoked potential to be elicited results in potentially salvageable damage.

Surveillance of hospital-associated infections

A totally laboratory-based system for surveillance of hospital-associated infections is not sensitive enough, but may be a base for surveillance of urinary tract infections. The SENIC study has convincingly demonstrated that for the four most important hospital-associated infections in the U.S., active ongoing intense surveillance based on daily patient chart and/or Kardex reviews in itself reduces the infection rate. Studies in other countries indicate that for postoperative wound infections this holds true also outside the U.S. For other types of nosocomial infections, similar studies outside the U.S. are urgently needed. The SENIC study underlines the importance of infection control nurses, but also of well-trained hospital epidemiologists.

Spinal cord restitution following compression injuries in rats

Spinal cord compression injuries were produced in rats by applying weights to a plate 2.2 x 50 mm in size, placed on the exposed midthoracic dura covering the spinal cord. The influence of force and duration of compression was studied by using 3 different weights, 20, 35 and 50 g, applied for 1, 5 and 10 min. Postoperative neurological function was tested by the inclined plane method and the rats were observed for 3 weeks. Neurological impairment increased with force and duration of compression. It is therefore reasonable to conclude that patients suffering from spinal cord injury should be investigated immediately for signs of persistent cord compression. If this is present, early decompression might be of value, although nothing is known in man concerning the limits of force and duration of compression permitting postoperative neurological recovery.

Methodological analysis of an experimental spinal cord compression model in the rat

A technique for producing graded spinal cord compression injuries in rats is described. A metal plate 2.2 x 5.0 mm in size is applied to the exposed spinal dura and loaded with weights. Neurological function is tested postoperatively on an inclined plane. Reading of the maximal angle of rat performance on this plane was found reproducible on comparison between different observers. Laminectomy per se had a minimal effect on the performance. Compression of 35 g for 5 min caused a pronounced but incomplete injury, with almost total recovery within 14 days and with no difference between animals on artificial respiration and those breathing spontaneously. Animals whose spine was fixed during the compression had a better outcome than those without such fixation.

Sucralfate versus placebo in reflux esophagitis. A double-blind multicenter study

The healing capacity and symptom relief were studied in 138 patients with symptomatic endoscopically verified reflux esophagitis treated with sucralfate (n = 69) or placebo (n = 69), 1 g four times daily (granules suspended in half a glass of water), for at most up to 12 weeks. The reflux esophagitis (modified Savary-Miller scale) was distributed with 71 patients having grade 1, 39 patients having grade 2 or 3, and 28 patients having grade 4. All patients were told to follow the antireflux regimen. Antacid tablets were supplied, to be used only for the relief of severe pain, and were counted. The esophageal lesions were completely healed in 42% (sucralfate) and 35% (placebo) after 6 weeks of treatment (NS). Corresponding cumulative healing rates at 12 weeks of treatment were 54% and 41% (NS), respectively. The symptom improvement, however, was significantly better in the sucralfate group after 3 weeks of treatment. The results indicate a symptomatic benefit of sucralfate in reflux esophagitis.

Secretion of newly synthesized proteins into the extracellular fluid of the rabbit hippocampus

Extracellular proteins were collected continuously from the hippocampus of the rabbit by slow perfusion of a protein-permeable thin tubing. After pulse labelling with radioactive amino acids via the tubing a rapid appearance of labelled proteins was seen in the extracellular fluid. The half-life of the proteins in the extracellular space varied between 15 min and 2 h. Protein fractions were separated with gel electrophoresis or HPLC. The extracellular fraction differed distinctly from intracellular proteins with respect to the labelling pattern.

Regulation of spinal cord blood flow in the rat as measured by quantitative autoradiography

Spinal cord blood flow (SCBF) and its response to alterations in blood gases and to systemic hypotension, haemodilution and barbiturate anaesthesia were measured in 47 rats at the level of Th 7-8 by quantitative autoradiography with [14C]iodoantipyrine ([14C]IAP) as tracer. During normocapnia and normoxia the mean SCBF values in the grey and white matter were 94 +/- 21 and 17 +/- 3 ml min-1 100 g-1, respectively. SCBF was highly dependent on PaCO2. Thus in hypercapnic animals (PaCO2 greater than 9 kPa) SCBF was increased in grey and white matter to 228 +/- 22 and 54 +/- 7 ml min-1 100 g-1, while during hypocapnia (PaCO2 less than 3.9 kPa) it was decreased to 64 +/- 14 and 11 +/- 2 ml min-1 100 g-1, respectively. Mean arterial blood pressure (MABP) was reduced by withdrawal of blood to 80 +/- 8 mmHg in a light hypotension group and to 53 +/- 11 mmHg in a severe hypotension group, compared with 126 +/- 13 mmHg in a control group. There was no significant difference in SCBF between the control group and the hypotension groups, suggesting that autoregulation is maintained down to an MABP of at least 50 mmHg. Normovolaemic haemodilution, with a reduction of the haematocrit from 50 +/- 2 to 33 +/- 3, increased SCBF to 113 +/- 9 ml min-1 100 g-1 in grey matter and to 21 +/- 12 ml min-1 100 g-1 in white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in brain temperature and free amino acids in normal and protein deprived suckling rats exposed to room temperature

Previous reports on early-induced protein-calorie malnutrition (PCM) in rats have indicated alterations in the concentration of free amino acids and of protein synthesis in the brain. Recently it was shown that early-induced protein deprivation (PD) retards the development of thermoregulation. This resulted in a failure to maintain a normal rectal temperature after short exposure to room temperature (+22 degrees C) still at the age of 20-25 days corresponding to changes seen in normal rats at an age of 10-15 days. In the present study, 20-day old PD and normal rats where examined with regard to the effect of exposure to room temperature on brain temperature and on brain free amino acids. The results show a similar reduction in brain and rectal temperature of the PD rats occurring within 30 minutes after exposure to room temperature. The reduction was in the range of 5 degrees C. PD rats kept in room temperature for 5 hours and then allowed to recover at 32.5 degrees C showed a slow increase in brain and rectal temperature but normal temperatures were not reached even after 1 hour. The concentration of free amino acids in the brain was examined in rats kept for 1 hour at room temperature or at 32.5 degrees C. In the PD rats kept at 32.5 degrees C, free aspartate and glutamate were reduced whereas taurine, GABA and glycine were increased as compared to their corresponding control rats. As a result of the reduced brain temperature in PD rats exposed to room temperature there was a reduction in free asparagine.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of the effects of preoperative whole-body bathing with detergent alone and with detergent containing chlorhexidine gluconate on the frequency of wound infections after clean surgery. The European Working Party on Control of Hospital Infections

In a prospective, randomized, double-blind, placebo-controlled study involving 27 surgical units in six European countries, the effect of preoperative whole-body bathing on two occasions with a detergent containing chlorhexidine (CHX+) on the incidence of wound infection in elective, clean surgery was compared with two bathings with a detergent without chlorhexidine (CHX-). In the CHX+ group 2.62% of 1413 patients and in the CHX- group 2.36% of 1400 patients subsequently became infected. The infection rate in the CHX+ group was 1.11 times that in the CHX- group with 95% confidence limits ranging between 0.69 and 1.82. Consequently, bathing patients twice preoperatively with chlorhexidine-detergent did not reduce the incidence of infection of clean wounds.

Analysis of the traction forces in different skull traction systems

During transportation of patients under skull traction, swinging of the weights produces acceleration forces that not only can cause pain and discomfort for the patient, but also can cause worsening of the cervical fracture or dislocation. Skull traction systems also involve friction forces. In a system with one pulley, the friction forces were 10 to 21.5% of the weight applied but, in a system with three pulleys (Stryker SurgiBed 965), they were as much as 65%. A new spring traction device that permits traction during transportation showed better physical characteristics than the hanging weight systems.

Hospital infection control in Sweden

In Sweden the 23 counties are respnsible for the medical care of their inhabitants. They own and run virtually all hospitals. This system facilitates a county-based hospital infection control system. The infection control team is based in the county hospital department of clinical bacteriology. It is headed by an MD clinical bacteriologist or, in some counties, by an infectious disease specialist. In the majority of cases this is a part-time job besides other duties in the department, but some ten hospital epidemiologists work full-time with infection control. Totally there are only some 50 full-time infection control nurse positions in Sweden. This means that on the average every infection control nurse is in charge of some 2,400 hospital beds, of which some 800 are somatic acute-care ones. These beds are situated in several hospitals, often at considerable distance from each other. The county-wise organization of hospitals facilitates infection control work. Medical and nursing procedures can be coordinated between the different hospitals within the county, and teaching is facilitated. However, the scarcity of infection control nurses makes it impossible to perform ongoing complete surveillance. Only surveillance based on laboratory reports can be performed routinely. In Swedish geriatric care there has been a strong movement not to accept incontinence as a reason for inserting and maintaining indwelling urinary catheters. This has greatly reduced urinary tract infections, and the rates of other infections as well. It has also reduced the costs in this type of medical care.(ABSTRACT TRUNCATED AT 250 WORDS)