Newborn screening for sickle cell disease. When is an infant 'lost to follow-up'?

Success of programs to screen newborns for sickle cell disease depends on timely follow-up. Education regarding fever and splenic palpation, and initiation of prophylactic penicillin therapy, will reduce morbidity and mortality and should occur prior to 4 months of age. However, contacting parents to permit implementation of care may be difficult, particularly in large urban populations; only nine (36%) of 25 infants recently identified as having sickle cell disease arrived at our institution for initial appointments. Medical providers must be aware of medical and legal obligations related to follow-up of newborns with sickle cell disease to prevent untoward events in "missed cases."

The use of radiotelemetry after discharge from the coronary care unit

Forty-six of 110 consecutive admissions to the coronary care unit (CCU) were monitored by telemetry after discharge from the unit. One of three patients with sudden cardiac death was resuscitated successfully and four patients developed atrial fibrillation which resulted in investigation by echocardiography and treatment with anticoagulants. Significant ventricular ectopic activity was detected in four other patients. Arbitrary selection of patients resulted in those with complicated courses in the CCU being more likely to be monitored by telemetry after transfer to the ward than those which were uncomplicated. There were no cases of sudden cardiac death in patients who did not have telemetry. The cost of telemetry was 2,775 pounds per system. All 19 districts in the North-West region of the UK responded to a questionnaire. Five of the 19 used telemetry but only two of these used the technique routinely after discharge from the CCU whereas four used radiotelemetry to monitor patients on the ward when coronary care beds were unavailable. Eight districts wanted telemetry but needed funds. We conclude that radiotelemetry is an inexpensive way to detect serious arrhythmias in patients transferred from the CCU to the general ward. Monitored from the CCU, cardiac arrest can be immediately detected and treated by experienced staff. Asymptomatic atrial fibrillation leads to prompt investigation by echocardiography and possible treatment with anticoagulants. The importance of noticing major ventricular ectopic activity is likely to increase with the possibility of selecting patients with a high risk of life-endangering arrhythmias so that antiarrhythmic drugs or techniques such as automatic defibrillators can be used appropriately.(ABSTRACT TRUNCATED AT 250 WORDS)

Gunshot wounds then and now

This review is a study of the development of the bullet and its effects, and the surgical treatment of gunshot wounds from John Hunter's time to the present day.

Oral dantrolene sodium for tonsillectomy pain: a double-blind study

Tonsillectomy in adults and older children is typically accompanied by 7 to 14 days of pain. On the basis of clinical observations of patients treated perioperatively with dantrolene sodium for malignant hyperthermia, we hypothesized that pharyngeal muscle spasms are a major factor in tonsillectomy pain. We entered 113 patients, 11 years of age and older, into a double-blind, placebo-controlled study to evaluate the effectiveness of dantrolene sodium in reduction of tonsillectomy pain. Patients were randomly assigned either dantrolene (1.5 mg/kg per day) or placebo orally four times a day for 5 days postoperatively. On a standardized questionnaire, the patient recorded pain, diet, activity level, analgesics, and side effects, daily for 2 weeks. Also, alkaline phosphatase (alk phos) and serum aspartate aminotransferase (SGOT) levels were determined before the operation and 2 weeks after. Patients who received dantrolene had no significant differences in subjective pain, diet, or activity level scores from those of patients who received placebo. Dantrolene patients did, however, require significantly less analgesic use than placebo patients (p = 0.034, 0.015, and 0.005 for postoperative days 2, 3, and 4, respectively). There was no significant difference in side effects or changes in liver enzyme between the dantrolene and placebo groups. We conclude that dantrolene sodium, given in the dosage noted, is effective in reduction of analgesic requirements after tonsillectomy.

Viscosity of mixtures of sickle and normal red cells at varying hematocrit levels. Implications for transfusion

Viscosity (eta) in a blood suspension is affected by the total hematocrit (HT) as well as by the deformability of the cells. The impact of these combined factors on the rheologic behavior of sickle cell suspensions and on guidelines for transfusion has not been explored fully. Therefore, the eta of mixtures of washed normal (AA) and sickle (SS) red cells was determined in a rotational viscosimeter as a function of the hematocrit level of SS cells (HS), HT, oxygen tension (PO2), and shear rate. The ratio HT:eta can be taken as an index of potential oxygen delivery. The optimal HT (for maximum HT:eta) became progressively higher as the HS or the HS:HT ratio was lowered: at a given HT, HT:eta rose with a decrease in HS, especially at low HS values. These data support the concept that simple transfusion alone is not as beneficial to the patient as exchange transfusion and that substantial benefit can be obtained by bringing the patient to very low HS levels. The finding that eta rose with HT more steeply when the HS:HT ratio rather than HS was held constant suggested that the absolute level of HS may be more useful than the HS:HT ratio as a guide for a transfusion regimen.

Salvage mechanisms for regeneration of adenosine triphosphate in rat cardiac myocytes

Since mitochondrial oxidative phosphorylation does not produce sufficient adenosine triphosphate for rapid restoration of contractile function in myocardium reoxygenated after ischaemia alternative non-oxidative routes by which purine nucleosides or bases may be used to increase the cytoplasmic adenine nucleotide pool were studied. Comparative rates of uptake and salvage of adenosine, adenine, and hypoxanthine were determined using myocytes isolated from adult rat heart. For each precursor reactions limiting the overall rate at which substrate in the extracellular fluid is incorporated into the intracellular adenosine triphosphate pool were identified. Adenosine was salvaged at twice the rate seen with adenine in the presence of ribose, whereas the rate of salvage of hypoxanthine, in the presence of ribose, was only 5% of that for adenosine. Adenine may be an advantageous substrate since high concentrations of adenine are not inhibitory to salvage and do not influence cardiac haemodynamics. Salvage of hypoxanthine appeared to be limited by the rate of adenylosuccinate synthetase, which was present at less than 1% of the adenylosuccinase rate in rat, rabbit, and beef heart. In addition, since salvage of bases is dependent on the availability of phosphoribosylpyrophosphate rates of synthesis of phosphoribosylpyrophosphate were measured in whole myocytes from ribose and in cytoplasmic extracts from ribose and from ribose-5-phosphate. Metabolic sites were identified at which interventions designed to accelerate salvage rates might best be directed.

Changes in visual functions of children exposed as infants to prolonged illumination

The visual system can be modified by early experience. Many infants requiring extensive medical treatment spend time in neonatal intensive care units in which they experience prolonged and relatively intense illumination. Visual functions were measured in a group of 7-year-old children who, as infants, were in intensive care for treatment of neonatal jaundice. Using procedures disguised as games, these children were tested for spatial and temporal resolution, receptor functions, and binocular vision. Especially in children whose eyes had not been shielded, deficits were found in color vision, spatial contrast sensitivity, and stereopsis, but not in rod vision.

Metabolism and salvage of adenine and hypoxanthine by myocytes isolated from mature rat heart

Adenine and hypoxanthine can be utilised by cardiac muscle cells as substrates for the synthesis of ATP. A possible therapeutic advantage of these compounds as high-energy precursors is their lack of vasoactive properties. Myocytes isolated from mature rat heart have been used to establish in kinetic detail the capacity of the heart to incorporate adenine, hypoxanthine and ribose into cellular nucleotides. Maximum rates of catalysis by enzymes on the salvage pathways have been established. Whilst the rate of incorporation of adenine into the ATP pool appears to depend upon intracellular concentrations of adenine and phosphoribosylpyrophosphate, for hypoxanthine the pattern is more complex. Hypoxanthine is salvaged at a slow rate compared with adenine, and is incorporated into GTP and IMP as well as into adenine nucleotides. The rate of incorporation of hypoxanthine into both IMP and ATP is accelerated in myocytes incubated with ribose. However, the rate-limiting reaction appears to be that catalysed by adenylosuccinate synthetase, for the rate of ATP synthesis is not accelerated when hypoxanthine concentration is increased from 10 to 50 microM, while the rate of IMP synthesis is more than doubled. Adenine and hypoxanthine phosphoribosyl transferases are present in equal catalytic amounts, but rat cardiac myocytes have very little adenylosuccinate synthetase activity. Exogenous ribose is incorporated into adenine nucleotides in amounts equimolar with adenine or hypoxanthine.

Resolution of right atrial thrombus shown by serial cross sectional echocardiography

A 78 year old woman with congestive cardiac failure developed pulmonary embolism. Cross sectional echocardiography detected an undulating fusiform mass attached to the lateral wall of the right atrium and protruding through the tricuspid valve. Serial cross sectional echocardiograms showed a reduction in the size of the mass, and by three months the mass was immobile and attached by a broad base to the lateral atrial wall. The mass was assumed to be a thrombus, and treatment with heparin and oral anticoagulants appeared to prevent the development of further pulmonary emboli.

5'-Nucleotidase activity of isolated mature rat cardiac myocytes

Specific location of 5'-nucleotidase in the heart has been uncertain, some authors citing evidence for an exclusively non-myocyte location, while other data point to the existence of cytoplasmic and membrane-bound fractions. Single myocytes isolated from mature rat heart, and free of endothelial or interstitial cells, have been used to establish that muscle cells of the myocardium are rich in 5'-nucleotidase, exhibiting activity sufficient to account for the total myocardial content of this enzyme. All 5'-nucleotidase is accessible to extracellular AMP. Inhibitors of 5'-nucleotidase and adenosine transport have been used to establish that only the adenosine component of adenine nucleotides is taken up by myocytes, but hydrolysis of AMP by 5'-nucleotidase does not commit the adenosine formed to transport across the sarcolemmal membrane. Myocytes also have ecto-phosphatases which hydrolyse ADP and ATP.

Accumulation and salvage of adenosine and inosine by isolated mature cardiac myocytes

Reoxygenation of ischaemic, energy-depleted heart does not result in sufficiently rapid regeneration of normal adenine nucleotide concentrations for preservation of cardiac function and structure. Salvage of nucleoside as a mechanism for restoration of ATP in the post-ischaemic myocardium is limited by efflux of adenosine during ischaemia. Isolated cardiac myocytes have been used to establish the kinetics of uptake and salvage of adenosine and inosine, measuring the distribution of radioactive nucleoside incorporated into ATP, ADP and AMP. Maximum rates of catalysis of reactions on the salvage pathway, and of enzymes competing for substrates on the pathway, have been established in myocyte extracts. Myocytes have little capacity to salvage or catabolise inosine. Enzyme measurements indicate that salvage of adenosine should proceed at 7-8-times the rate exhibited by intact myocytes dependent upon extracellular adenosine as substrate. The data indicate that the rate of transport of adenosine is not determined by its metabolic utilization, but is the rate-limiting step in the salvage of adenosine.

A survey of patients selected by general practitioners for home care of suspected myocardial infarction: arrhythmia detection using Holter monitoring

From the Lancaster district (pop. 50 000) 101 patients were selected for home care of suspected acute myocardial infarction (AMI) by their general practitioners (GPs) and 78% were seen within 6 h (44% within 2 h). Infarction was confirmed in 54 cases compared with 203 in the coronary case unit over the same period. Reasons given for home management were stable condition (48%), diagnostic doubt (34%), patient preference (18%), good home (15%), age (14%). Holter ECGs from 97 patients were analysed to see if arrhythmias were undetected clinically and recordings of at least 20 h were obtained in 88 (91%). Symptoms drew attention to atrial arrhythmias in 5 patients. Ventricular premature beats were recorded in 96% of the AMI group (84% of the non-MI), ventricular tachycardia in 21% of the AMI patients (5% non-MI), atrial fibrillation in 25% of AMI (7% non-MI) and complex ventricular ectopic activity (Lown 3-5) was found in 81% of the AMI (58% of the non-MI). We conclude that the GPs in the Lancaster district select patients for home care of AMI on clinical and social grounds rather than time after onset. Holter ECG recordings reveal major arrhythmias which are usually undetected clinically and are at least as common as those found in CCU treated patients. Further studies involving larger numbers of home treated patients monitored early are required to identify criteria for home care.

The value of contrast cross-sectional echocardiography in the diagnosis of tricuspid regurgitation

Reflux of contrast into the inferior vena cava and hepatic veins during held expiration was studied in 70 subjects using subxiphoid 2D echocardiography. Venous reflux of contrast occurred in 7/19 normal subjects (group 1), 13/17 patients with definite or probable tricuspid regurgitation (group 2), 10/13 patients with congestive cardiac failure (group 3) and 10/21 patients with miscellaneous cardiac conditions unlikely to be associated with tricuspid regurgitation (group 4). There were 30 patients with no appearance of microbubbles in the inferior vena cava and hepatic veins on suspended expiration: 10 of these had reflux of contrast when breathing was restarted. Of the 17 patients with atrial fibrillation, 14 showed reflux, but there were 3 patients with no reflux. We conclude that the appearance of contrast in the IVC and hepatic veins may be found in many subjects in whom tricuspid regurgitation is unlikely on clinical grounds, even when recordings are taken in held expiration. Atrial fibrillation alone does not necessarily cause venous reflux of contrast. Demonstration of simple venous reflux of contrast by 2D echocardiography is too non-specific for routine use in the detection of tricuspid regurgitation.

Two dimensional echocardiography and the tricuspid valve. Leaflet definition and prolapse

The tricuspid valve was studied in 143 subjects using two dimensional echocardiography. The groups studied were 40 normal subjects, 31 patients with mitral valve prolapse, 22 with clinically probable tricuspid valve prolapse, 20 with congestive cardiac failure, and 30 with miscellaneous cardiac conditions but no features of right heart disease. Using multiple views it was possible to record all three leaflets in 74.8% of cases and anterior and septal leaflets in 95%. Prolapse of the tricuspid valve was recognised in 13 patients: six (19.5%) of the group with mitral valve prolapse and seven (6%) of the remaining patients. Prolapse of all three leaflets was shown in one patient, anterior and septal prolapse in six patients, anterior and posterior in three patients, septal leaflet prolapse alone in two patients, and anterior alone in one patient. Two dimensional echocardiography allows definition of individual tricuspid leaflets and prolapse of any or all leaflets can be diagnosed. Tricuspid valve prolapse is commonly associated with prolapse of mitral valve leaflets but isolated cases are recognised.