Triquetral-lunate arthritis secondary to synostosis

Until recently the problem of painful, symptomatic arthritis of the wrist secondary to congenitally incomplete separation of carpal bones has been infrequently recognized. Five patients with either excessive stress loading or trauma had eight symptomatic wrists with congenitally incomplete separation of the triquetral-lunate joint. Three of these patients had bilateral symptoms. Six of the wrists had been treated by a limited wrist arthrodesis of the triquetral-lunate joint resulting in asymptomatic wrists and improved range of motion. It appears that patients with this congenital condition poorly tolerate stress loading or trauma secondary to deficient intra-articular cartilage formation resulting in a clinical and anatomic state similar to degenerative arthritis. We suggest a limited wrist arthrodesis as definitive treatment for symptomatic congenitally incomplete separation of the triquetral-lunate joint, with possible application in incomplete separation of the other intercarpal joints.     

Influence of methylphenidate on brain development – an update of recent animal experiments

Methylphenidate (MPH) is the most commonly used drug to treat attention deficit/hyperactivity disorder (ADHD) in children effectively and safely. In spite of its widespread application throughout one of the most plastic and sensitive phases of brain development, very little is known to date about its long-term effects on brain structure and function. Hence, this short review updates the influence of MPH on brain development, since recent human and animal studies suggest that MPH alters the dopaminergic system with long-term effects beyond the termination of treatment.     

Effect of conjugated estrogens on platelet function and prostacyclin generation in CRF

In a double-blind, randomized, placebo-controlled cross-over study, we investigated in seven patients with chronic renal failure the effect of conjugated estrogens (0.6 mg/kg/day for 5 days) on template bleeding time and on thromboxane A2 (TxA2), beta-thromboglobulin (beta-TG) and prostacyclin (PGI2) concentrations in blood emerging from the template bleeding time incisions. Administration of conjugated estrogens resulted in a significant shortening of the bleeding time in six out of seven patients with a maximum effect 7 and/or 14 days following treatment. Both TxA2 (measured as thromboxane B2, TxB2) and beta-TG release in bleeding time blood were significantly higher following administration of conjugated estrogens as compared to placebo administration. No difference was seen in endothelial PGI2 (measured as 6-keto-prostaglandin F1 alpha) formation when patients were treated with conjugated estrogens as compared to placebo administration over the 28 day observation period. We conclude that in patients with chronic renal failure, infusion of conjugated estrogens results in a significant shortening of the bleeding time together with an increase in platelet reactivity, as indicated by an increase of TxA2 and beta-TG concentration in the microvasculature. No effect was seen on PGI2 production, thereby excluding a major effect on vascular prostaglandin metabolism.     

Morbidity among employees engaged in the manufacture or formulation of chlorpyrifos.

The prevalence of selected illnesses and symptoms during 1977-85 was compared between 175 employees potentially exposed to the organophosphate insecticide chlorpyrifos and 335 matched controls with no history of exposure to organophosphates. Subjects were subdivided into three exposure intensity groups on the basis of job title and air monitoring data for dose response testing. This classification scheme was shown roughly to correlate with plasma cholinesterase inhibition in the workers. No statistically significant differences in illness or prevalence of symptoms were observed between the exposed and unexposed groups or among the three exposure subgroups. Potentially exposed employees did report symptoms of dizziness and of malaise and fatigue relatively more often than subjects from the comparison group; however, further analyses by exposure level, process area, or time did not support a relation with exposure. No cases of peripheral neuropathy were seen among the exposed workers. Although the sample size was small and the statistical power limited, the cumulative exposures likely to have been experienced by this workforce exceed those to be expected for individuals using the product as recommended. The absence of exposure related adverse effects, including neurological impairment, is reassuring.     

Pressure stability of nasal CPAP and bilevel devices

Summary Question of the study   Nasal continuous positive airway pressure (CPAP) prevents collapse of the upper airway during sleep in patients with obstructive sleep apnea provided that a positive transmural pressure can be maintained during inspiration. We examined pressure-flow characteristics in seven CPAP and bilevel devices during spontaneous breathing.
Methods   The CPAP devices were set to a pressure level of 9.8  hPa (10  cm H₂O) and adapted to a pneumotachograph using a standard CPAP hose and an outlet valve. We continuously measured flow, volume and pressure during resting ventilation and increasing voluntary hyperventilation and analysed the dependence of the variables on a breath-to-breath basis.
Results   Mean CPAP pressures differed between the devices (9.9 – 10.6  hPa) despite the same settings. In all machines pressure fell during inspiration to 8.4 – 9.8  hPa and increased during expiration to 11.1 – 11.7  hPa. This effect increased with higher flow rates. Maximum expiratory pressures rose to 12 – 19  hPa at peak flow rates of 2 l/s, mean expiratory pressures to 9.5 – 16  hPa. Inspiratory pressures dropped to 8.5 – 4.5  hPa (minimum) and 10.5 – 6.0 (mean). Bilevel devices showed a higher stability than CPAP devices. Pressure swings during the respiratory cycle increased the additional work of breathing.
Conclusions   Due to differences in mean and effective CPAP levels CPAP devices are not simply exchangeable but should be individually adapted. Patients with higher minute ventilation might benefit from more stable CPAP machines. The impact on patients' compliance remains to be evaluated.     

Enchondroma of the hand – clinical evaluation of diagnosis, surgical treatment, and outcome

Summary Enchondroma are benign cartilaginous tumors and are localized most often at the site of the phalanges. Between 1982 and 1993 73 patients with monostotic enchondroma and 5 patients with polyostotic enchondroma were operated at our clinic. Clinical signs of monostotic tumors were pathological fracture (38.4 %), pain or swelling. Eleven percent of cases were accidental findings. Surgical treatment was performed by complete removal of the tumors and filling the bone cavity with autologous spongiosa taken from the pelvic bones, the elbow, or the radius. Three patients (4.1 %) had to be operated a second time due to wound infections and hematoma. In one case Sudeck's dystrophy was diagnosed. One patient (1.4 %) developed a recurrent tumor. Our follow-up examination of 65 patients showed that 77 % of the patients with monostotic enchondroma achieve very good or good functional long-term results after this operation, but only 40 % of the patients with polyostotic enchondroma.      

Alternative Treatments for Asthma: Assessing the Need

Alternative treatments such as troleandomycin methotrexate, gold, and intravenous gamma globulin are sometimes considered for severe asthmatics to minimize the need for systemic corticosteroids and reduce adverse effects. These alternative therapies may also be associated with significant toxicity and expense. The ability to reduce corticosteroid use and the need for alternative treatment interventions in 125 pediatric patients at our institution were reviewed. Because corticosteroid requirements were reduced significantly, only 23 of 125 children evaluated were considered for treatment alternatives with only 10 receiving such therapy. This study emphasizes the importance of a thorough and comprehensive review of corticosteroid requirements and usage prior to initiating alternative approaches to treatment in moderate to severe asthmatics as well as in patients thought to be “steroid-dependent.”     

Separation of rare cell subpopulations with the aid of biotin-labelled ligands

A universal method for selection of surface marker-positive cells is described. The cells, admixed with an excess of surface marker-negative cells, are In-st labelled with a specific biotinylated ligand and then isolated with the aid of monoclonal, anti-biotin coated beads. The method enables selection and isolation of cells with a frequency as low as 10^-4. The ligand can be an antigen (for selection of infrequent antibody-producing cells), an antibody (for selection of surface antigen-positive cells) or other molecules (for selection of specific receptor-positive cells).