Oral iron chelation therapy with deferiprone. Monitoring of biochemical, drug and iron excretion changes

The oral iron chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1, deferiprone, CAS 30652-11-0) has been given daily for 3-11 months to 6 transfusion dependent iron loaded patients (myelodysplasia (MDS) 2, Diamond-Blackfan anaemia 1, thalassaemia intermedia 1, thalassaemia major 2). Daily doses of 3 g, 2 x 2 g and 3 x 2 g were administered for the first 2-7 months. Daily doses of 2 x 3 g were also used for periods up to 4 months. Urine iron excretion following 3 g of L1 was found to be related to the number of previous transfusions but not to serum ferritin or the amount of L1 excreted. In each case 24 h urinary iron excretion in response to 3 g L1 ranged from 5-21 mg in MDS, 13-25 mg in a thalassaemia intermedia and a Diamond-Blackfan patient and 16-110 mg in thalassaemia major patients. Further increases of urinary iron were observed in all the patients when the daily dose was increased. Serum ferritin levels have fluctuated but overall have remained unchanged. Biochemical assessment did not show any major abnormalities ascribed to L1 except from subnormal serum zinc levels in two patients and white blood cell absorbate in another. In a separate study we have compared urinary L1 and iron excretions in 7 transfusional iron loaded patients. In all the cases the concentration of L1 was in excess of iron and higher than the level required for 100% iron binding. There was no other apparent correlation between the concentrations of L1 and iron in the urines studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway obstruction in neonates and children: surgical treatment

OBJECTIVE

This review of 54 infants and children with airway obstruction who were treated surgically emphasizes the importance of the surgical indications with respect to various anomalies causing airway obstruction and the surgical approach to their management.

PATIENTS

There were 4 etiologic groups of airway obstruction. Group A comprised 12 infants with subglottic stenosis; Group B--20 infants with tracheomalacia; 21 patients (Group C) with anatomic narrowing of the trachea; and 1 infant (Group D) with laceration of a main bronchus.

METHODS

The surgical procedures performed included anterior laryngotracheal decompression in 12 infants, aortopexy in 19; 1 pulmonary arteriopexy; tracheal stenting with an autologous rib graft in 3 and with Marlex mesh in 1. Tracheal widening, using a free tibia autologous graft, was performed in 3 patients; transbronchoscopic excision in 12; anterior tracheal wedge resection in 4, and segmental tracheal resection and anastomosis in 1 patient. The lacerated bronchus was repaired with fine Dexon sutures.

RESULTS

There were no operative deaths. With respect to the original indications for surgery, there were 3 failures--2 in Group A and 1 in Group C. Two patients died from causes unrelated to the procedures--one 10 days postoperatively, and the other 3 months after surgery.

CONCLUSIONS

The surgical approach to tracheal obstruction in infants and children offers effective treatment, with no operative mortality, a low complication rate, and good long term survival.

Influence of biological response modifiers: measurement of tumor blood flow and temperature

Human recombinant interferon-alpha-2b (IFN) is known to inhibit growth of both normal and tumor cells and to stimulate immune effector cell function. We have previously shown that IFN and other biological response modifiers augment accumulation of radiolabeled antibodies in tumors. This investigation demonstrates that 30 min post i.m. administration of IFN significantly (p < 0.01) enhances tumor perfusion in tumor-bearing mice and persists for a much longer time than in normal tissue, which, in part, may contribute to the enhanced tumor uptake of radiolabeled monoclonal antibodies within 1.5 h of their administration. Histological examinations of tumors obtained from animals receiving IFN 72 h previously did not show changes in inflammatory cells. Our investigation shows that laser Doppler flowmetry and color Doppler imaging can provide an excellent means of measuring tumor perfusion changes in small living animals where radioactive tracers cannot be used.

Emergency department utilization by adolescents

PURPOSE

To review adolescents' utilization of a hospital emergency department (ED) in a rural area, to identify their characteristics, and to explore their motivation to seek health care in this setting.

METHODS

A retrospective chart survey of all 4932 adolescent visits (ages 12-18 years, 55.5% females) to the ED in a small town with a population of 55,000 serving a rural area was conducted for the calendar year 1989. Chief complaints and diagnoses were retrospectively categorized according to six groups: injury, pulmonary problems, Ob/Gyn, infection, nonspecific pain (complaint)/no diagnosis (diagnoses), and "other."

RESULTS

There was an increasing number of visits with increasing age. Adolescents with private insurance, who accounted for 50% of patients, were more likely than self-paying adolescents (14%) and adolescents on Medicaid (36%) to have a primary care source and to have access to a telephone. Injury was the most common diagnosis with motor vehicle accidents (MVA) accounting for 15% of all injuries. Self-paying adolescents and those on Medicaid were more likely to be diagnosed with an infection or an Ob/Gyn problem than adolescents with health insurance. Only 5.9% of adolescents were admitted to the hospital service. 8.5% of adolescents were discharged from the ED without a diagnosis. 78% of these had complained about nonspecific pain.

CONCLUSIONS

Many adolescents in this rural area were found not to have an identified primary care source and to seek health care in EDs. Illnesses that could have been prevented or treated in a more cost-effective setting thus become "emergencies." Primary care sources are needed that are accessible and acceptable to adolescents.

Sequence of the phosphoprotein gene of pneumonia virus of mice: expression of multiple proteins from two overlapping reading frames

The gene encoding the phosphoprotein of the pneumovirus pneumonia virus of mice (PVM) has been cloned and sequenced. The gene is 903 nucleotides in length and contains a long open reading frame (ORF) capable of encoding a polypeptide of 295 amino acid residues. A smaller, second, overlapping ORF encoding a polypeptide 137 amino acids in length was also present. The large ORF directed the synthesis of a 39-kDa polypeptide and four additional polypeptides with masses of 37 kDa, 26 kDa, 23 kDa, and 16 kDa in vitro. The smaller polypeptides were generated by internal initiation on in-frame AUG initiation codons to generate carboxy co-terminal products. Western immunoblot analysis indicated that at least two of these proteins and several other related polypeptides are present in infected cells, and the possible origins of these are discussed. Western blot analysis using antiserum raised against a synthetic peptide and specific for the predicted second ORF product identified a polypeptide of 23 kDa in PVM-infected cells. The pattern of PVM P gene expression is unlike that of the closely related respiratory syncytial virus and is reminiscent of that of paramyxoviruses such as Sendai virus. This is the first example of a pneumovirus encoding multiple polypeptide products from a single mRNA in vivo.

Optimal regional anesthesia for circumcision

Dorsal penile nerve block (DPNB) is a useful procedure for analgesia in circumcision. It has minor complications and a reported failure rate of from 4% to 6.7%. To evaluate the intraoperative value of additional anesthesia of the perineal nerves--a branch of the pudendal nerve--during circumcision, we conducted a prospective randomized double-blind study on 250 adults. The postoperative period was not studied. The subpubic space technique of DPNB was used. Patients received DPNB (Group I) or DPNB with an additional ventral injection (Group II) for perineal nerve analgesia. Seventeen patients (13.6%) from Group I suffered pain. Of these, nine (7.2%) had discomfort and mild pain but no supplemental analgesia was needed. In the remaining eight patients, however, it was necessary to add local analgesia. This represents a total failure rate of 6.4%. On the other hand, only six patients (4%) in Group II had a mild diffused discomfort with no need for additional local anesthesia (P < 0.01). The average operating time was 12.4 +/- 2.7 min (range 9-22 min) in Group I and 10.7 +/- 1.6 min (range 8-15 min) in Group II (P < 0.001). We think that perineal nerves play an important part in innervation of the penis and must be anesthetized during the penile block.

Acute scrotal pain complicating familial Mediterranean fever in children

Twenty-nine children with familial Mediterranean fever presented with 39 attacks of acute scrotal pain. Of these, 25 patients had an acute scrotum complicating familial Mediterranean fever and only four had testicular torsion. Scrotal pain was the only manifestation of a familial Mediterranean fever crisis in 36 episodes and in 15 boys scrotal involvement was the first manifestation of the condition. Fourteen patients were treated medically. Of 15 patients who underwent scrotal exploration there were no definite diagnostic findings in 11 and four had testicular torsion. Three cardinal features strongly suggest the diagnosis of acute scrotum in familial Mediterranean fever in a boy of Mediterranean origin with a relevant family history: recurrent scrotal pain or swelling; body temperature above 37.5 degrees C; and gradual onset of pain, usually of more than 12 h duration. Conservative management can safely be undertaken in these boys without fear of losing a salvageable testis.

Peritoneal ventilation: an animal model of extrapulmonary ventilation in experimental adult respiratory distress syndrome

Adult respiratory distress syndrome (ARDS) is a critical medical problem in which severe arterial hypoxemia is often poorly responsive to conventional modes of mechanical ventilation. We studied the efficiency of mechanical ventilation of the peritoneal cavity in rabbits with experimental ARDS caused by lung lavage. The study shows that peritoneal ventilation is significantly effective in oxygenation of hypoxemic animals with ARDS and is also effective for carbon dioxide elimination. Peritoneal ventilation may be considered as an investigational method for extrapulmonary oxygenation in severe intractable hypoxemia caused by ARDS.

In vitro metabolism of theophylline by rat and human liver tissue

1. The metabolism of theophylline was studied in the recently developed, precision-cut, liver slice system. Metabolism of theophylline by rat and human liver slices increased over a 6 h incubation period. 2. Rat liver slices produced 1,3-dimethyluric acid, 1-methyluric acid, and uric acid. Human liver slices produced the same metabolite, as well as 3-methylxanthine. 3. Liver slices and microsomes obtained from the Aroclor-1254 pretreated rats metabolized theophylline at a 10-15-fold greater rate than those obtained from control rats. 4. When theophylline was administered orally to the control and Aroclor-1254 pretreated F-344 rats, the same metabolites were present in the urine as were produced in both in vitro systems. Much less theophylline and more metabolites were found in the urine of the Aroclor-1254 pretreated rat. 5. This study demonstrates that precision-cut slices maintained in the roller culture system can serve as a reliable in vitro method to assess the metabolism of xenobiotics.

Studies of aluminium mobilization in renal dialysis patients using the oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one

The oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one (L1, deferiprone, CAS 30652-11-0) has been tested in 11 renal dialysis patients, 10 for aluminium and 1 for iron mobilization. L1 was administered just after the patients were placed on the haemodialyser and blood samples were collected before haemodialysis at 1 h and for some patients at longer intervals. Plasma aluminium levels before treatment ranged from 12 to 264 micrograms/l. A mean increase of 90% was observed within the first hour of oral administration in 6 patients who received a dose of L1 of 40-60 mg/kg. Plasma aluminium levels then progressively decreased after this period. Three patients with plasma aluminium of 30-66 micrograms/l who received a dose of L1 of less than 30 mg/kg had no significant changes in their plasma aluminium. In 2 other cases administration of L1 resulted in an over 30-fold increase of aluminium concentration in the dialysate of a continuous ambulatory peritoneal dialysis patient and of over 3 times the iron concentration in the dialysate of an iron loaded haemodialysis patient. In the last patient HPLC analysis of the dialysate samples obtained from the haemodialyser has shown complete clearance of L1 within 4 h but not of its glucuronide metabolite within 6.5 h of the L1 administration. No toxic side effects were observed in any of the 11 patients who received oral L1. These are the first clinical trials of an oral chelator in renal dialysis patients which suggest that oral L1 and possibly other alpha-ketohydroxypyridine chelators may have a use in the treatment of patients with aluminium overload.

The management of epidural haematomas--surgical versus conservative treatment

We treated 14 children and infants during 1990-1993 who suffered severe head trauma with consequent epidural haematomas. We tried, in accordance with several recent publications, to follow part of them conservatively. The report describes the clinical and radiological features of these patients and discusses the criteria for conservative management of epidural haematoma in paediatric patients. The relevant literature is reviewed.

CT after intracranial intraarterial thrombolysis for acute stroke

PURPOSE

To determine the incidence, appearance, and clinical significance of lesions mimicking intraparenchymal hemorrhages on CT in patients treated with intracranial intraarterial thrombolysis for acute strokes.

METHODS

Ten cases of acute stroke treated with direct intraarterial urokinase infusion were retrospectively reviewed. Clinical and radiographic findings before and after therapy were all evaluated.

RESULTS

Six (60%) of the 10 patients showed areas of increased attenuation on CT shortly after thrombolytic therapy. The lesions were associated with clinical deterioration in two cases (20%); in these two cases the lesions persisted on CT for several days. The lesions were asymptomatic in two (20%) cases; the lesions cleared on CT within 24 hours in those two patients. In two (20%) patients, immediate clinical improvement was evident despite the radiodense areas. These lesions also cleared within 24 hours. CT Hounsfield unit measurements of four of the lesions revealed very high Hounsfield units in two lesions, only one of which was a symptomatic lesion. MR in two cases revealed residue of hemorrhage.

CONCLUSION

Intraparenchymal areas of increased attenuation may be seen on the CT scans of patients after intraarterial thrombolysis. The density is often at least partially attributable to contrast extravasation. The lesions should not necessarily be interpreted as hemorrhage alone, especially in the absence of clinical deterioration. Rapid clearing may be a positive prognostic sign.

Intra-operative ultrasonography as a routine screening procedure in biliary surgery

Intra-operative cholangiography and ultrasonography were compared in screening for unsuspected common bile duct stones. In 57 consecutive patients both procedures were performed, and in 60 only ultrasonography was used. Although the study was conducted during the initial self-teaching period (regarding ultrasonography) the results show an advantage of this relatively new diagnostic technique. The false positive rate was lower and consequently the predictive value of a positive test was higher for intraoperative ultrasonography. The main benefit would thus be a lower rate of negative common bile duct explorations. Our early results suggest that the general surgeon would need only a short adaptation period to this imaging modality, which would seem to be a valuable alternative to intra-operative cholangiography.

Phenothiazine treatment and respiratory distress syndrome in a child

An 11-year-old boy who was treated with a relatively high dose of methotrimeprazine meleate (Levemepromazine) a phenothiazine antipsychotic drug, was admitted to the pediatric intensive care unit suffering from respiratory distress syndrome. He required intensive treatment and support for 13 days. The persistent effects of methotrimeprazine meleate on various organs are typical of the prolonged biological action of the phenothiazine metabolites. The association of phenothiazine overdose and respiratory distress syndrome merits consideration.

Guardian: an experimental system for intelligent ICU monitoring

We are developing an intelligent agent for patient monitoring named Guardian. It is applied to the post-operative monitoring and therapy management of cardiac surgery patients. Even though Guardian is an experimental system so far, we anticipate that in the short term it will be integrated with existing ICU information systems and critically evaluated on simulated patient cases. In evaluating the system, we aim to demonstrate that human-machine cooperation in information overload situations can improve the work environment of clinicians, improve health care delivery, and ultimately reduce health-care costs.

Acute lung injury at Baragwanath ICU. An eight-month audit and call for consensus for other organ failure in the adult respiratory distress syndrome

To test the expanded definition of acute lung injury (ALI), we prospectively, over a period of 8 months, studied all adult ICU admissions who fitted the definition. Our study consisted of 83 patients with the adult respiratory distress syndrome (ARDS) and 60 with mild to moderate ALI. Sepsis and trauma were the most common diagnoses on admission. The overall mortality rate was 45 percent for ARDS and 38 percent in the other group. Mortality rose significantly with associated other organ failure, the incidence of which was as follows: hepatic, 39 percent; cardiac, 38 percent; hematologic, 22 percent; renal, 21 percent; neurologic, 5 percent. Sepsis syndrome eventually occurred in 73 percent and septic shock in 38 percent of all cases of ALI. We found the expanded definition a useful grading system and consider this definition of ARDS to be currently the best. There are, however, problems with the determination of lung compliance, the effect of inverse ratio ventilation, and the lack of consensus in defining other organ failure.

Selection of a new generation of orally active alpha-ketohydroxypyridine iron chelators intended for use in the treatment of iron overload

The prospect of selecting oral alpha-ketohydroxypyridine chelators intended for clinical use in iron overload has been examined using several animal models of efficacy and toxicity. Studies using iron dextran-loaded mice labelled with 59Fe have shown that only the 1-substituted methyl, ethyl, (n)propyl, allyl, cyclopropyl, 2'-methoxyethyl, 3'-ethoxypropyl, or 2-methyl- or 2-ethyl-3-hydroxypyrid-4-one chelators were orally effective in increasing iron (59Fe) excretion by comparison to intraperitoneally administered desferrioxamine at the same dose (250 mg/kg). In contrast, chelators containing -H, mono- or dihydroxyalkyl and diethoxyethyl 1-substituents caused very little or no increase in iron (59Fe) excretion by the oral or intraperitoneal routes. In vitro studies using ferritin and haemosiderin have shown that equivalent iron release took place with both groups of chelators irrespective of their in vivo effects. In most cases there was no correlation between the n-octanol/water partition coefficient (Kpar) and iron removal efficacy but positive correlation between the lipophilicity and acute or subacute toxicity of these chelators in rats. The most toxic chelator in the chronic toxicity studies in rats was the lipophilic 1,2-diethyl-3-hydroxypyrid-4-one (EL1NEt). The most effective chelator in increasing iron excretion in mice and rabbits was 1-allyl-2-methyl-3-hydroxypyrid-4-one (L1NAII), and the chelator with the highest safety margin in mice and rats was 1,2-dimethyl-3-hydroxypyrid-4-one (L1). Overall the oral effectiveness in increasing iron excretion by these chelators in animals does not appear to be related to their lipophilicity or their ability to mobilise polynuclear iron in vitro but rather to other properties possibly related to their rate of biotransformation and excretion.

High-dose adrenaline in adult in-hospital asystolic cardiopulmonary resuscitation: a double-blind randomised trial

Forty intensive care unit patients requiring cardiopulmonary resuscitation were randomised to receive either the standard dose of adrenaline (1 mg every five minutes) or high-dose adrenaline (10 mg every five minutes). In the majority of patients, overwhelming sepsis was the major contributing factor leading to cardiac arrest. In this group of patients no difference could be detected in response to high-dose adrenaline compared with the standard dose. Although no side-effects were noted with this high dose of adrenaline, more investigation is required prior to its routine use in cardiopulmonary resuscitation.

Evaluation of gender differences in urine specific gravity and serum electrolytes in response to varied fluid intake and ibuprofen use

Heat casualties and other conditions related to suboptimal fluid intake (FI) are common in the military. Current methods to assess FI do not address gender differences or medication use, specifically non-steroidal anti-inflammatory drugs (NSAIDs), which are commonly used in the field. Nine men and six women were prospectively studied while stationed in Saudi Arabia. Urine specific gravity and serum electrolytes were monitored as FI was varied before and after daily ibuprofen (IBP) ingestion. IBP impaired urinary dilution in both men and women, but differences were not statistically significant pre- and post-IBP or between genders. Use of IBP or other NSAIDs may confound usual methods to ensure adequate FI, and soldiers should be specifically questioned about their use before such assessments.

Early marked arytenoid calcification in a case of suspected foreign body

A case of early marked calcification of the arytenoid cartilages is presented in a patient with a suspected pharyngeal foreign body. The calcification on X-ray had the appearance of the expected foreign body. Calcification of the arytenoid cartilages is discussed.

Biguanide-associated lactic acidosis. Case report and review of the literature

PURPOSE

The biguanides are a class of oral hypoglycemic agents that are commonly used in the treatment of diabetes mellitus. Such agents include metformin, phenformin, and buformin. The use of phenformin was discontinued in the United States in 1976 because of probable association with lactic acidosis. However, metformin is currently in common use in many parts of the world. In this report, we describe a patient with severe lactic acidosis secondary to metformin administration, and review the literature relevant to biguanide-associated lactic acidosis.

PATIENT

We describe a diabetic man with end-stage renal failure and diabetes mellitus who was hospitalized with life-threatening lactic acidosis (lactate, 10.9 mmol/L). Unbeknownst to the hospital staff, he was being treated with metformin, which had been prescribed in Indonesia.

RESULTS

Arterial blood gas analysis revealed a pH of 6.76 and a bicarbonate level of 1.6 mmol/L prior to treatment. Following therapy, which included oxygen, volume expansion, other supportive therapy, and hemodialysis, the patient completely recovered and was discharged from the hospital.

CONCLUSIONS

Lactic acidosis can complicate biguanide therapy in diabetic patients with renal insufficiency. We review the literature relevant to the pathogenesis and therapy of biguanide-associated lactic acidosis. Physicians who have completed their training after 1976 may not be familiar with metformin and other biguanides, but with the increasing numbers of immigrants to the United States, physicians should be aware of the potential complications of these medications.

Septic shock: does adrenaline have a role as a first-line inotropic agent?

Fifteen adult patients, admitted to Baragwanath Hospital ICU with septic shock after adequate fluid loading and on no other inotropic agents, were given adrenaline in incremental doses. Oxygen transport and haemodynamic variables were monitored with each dose increment until a systolic blood pressure of 120 mmHg was obtained. This was reached on an average dose of adrenaline of 0.16 +/- 0.02 micrograms/kg/min. Mean arterial blood pressure increased by 22 +/- 2 mmHg mainly due to an increase in cardiac index (1 +/- 0.2 l/min/m2) and systemic vascular resistance index (130 +/- 41 dyn.s.cm.-5m-2) with a small increase in heart rate of 8 +/- 3 beats per minute. Oxygen delivery was increased with no significant increase in oxygen consumption and lactate levels increased. Adrenaline is therefore an effective initial inotropic agent. Patients may respond to lower doses than when used concurrently with other inotropic agents but there was still a significant dose variation in response. We cannot, however, exclude a deleterious effect on oxygen utilization.

Improved algorithms for searching restriction maps

We present algorithms for searching a DNA restriction enzyme map for a region that best matches a shorter 'probe' map. Our algorithms utilize a new model of map alignments, and extensive experiments prove our model superior to earlier approaches for certain applications. Let M be the number of map sites and P be the number of probe sites. Our first algorithm, which optimizes only over a restricted class of alignments, requires O(MP log P) worst-case time and O(M + P) space. Our second algorithm, which optimizes over all alignments, runs in O(MP3) time and O(M + P2) space, under reasonable assumptions about the distribution of restriction enzyme cleavage sites. Combining the algorithms gives a map-searching method that optimizes over all alignments in O(MP log P) time in practice. The algorithms' effectiveness is illustrated by searches involving a genomic restriction map of Escherichia coli.