Schwannomas and Their Pathogenesis

Schwannomas may occur spontaneously, or in the context of a familial tumor syndrome such as neurofibromatosis type 2 (NF2), schwannomatosis and Carney's complex. Schwannomas have a variety of morphological appearances, but they behave as World Health Organization (WHO) grade I tumors, and only very rarely undergo malignant transformation. Central to the pathogenesis of these tumors is loss of function of merlin, either by direct genetic change involving the NF2 gene on chromosome 22 or secondarily to merlin inactivation. The genetic pathways and morphological features of schwannomas associated with different genetic syndromes will be discussed. Merlin has multiple functions, including within the nucleus and at the cell membrane, and this review summarizes our current understanding of the mechanisms by which merlin loss is involved in schwannoma pathogenesis, highlighting potential areas for therapeutic intervention.     

HPV and precancerous lesions of anal canal in women: systematic review

Objective  

The infection caused by human papillomavirus (HPV) in the anogenital area is considered the most common sexually transmitted infection in the world. Although anal cancer is relatively uncommon in the general population, there has been a significant increase in incidence in recent years. In this review, we focused on research on anal lesions in women.     

Polyuria associated with an antibody to vasopressin.

1. A patient with polyuria in whom diabetes insipidus had been diagnosed was treated with Pitressin. Resistance to this therapy developed after 18 months and a circulating antibody to vasopressin was then demonstrated. Withdrawal of therapy led to a fall in titre of the antibody and an increase in maximal urinary concentration. 2. The antibody to vasopressin was associated with the IgA fraction of the serum immunoglobulins and its characteristics are described.     

The Evaluation of Leukocytes in Response to the In Vitro Testing of Ventricular Assist Devices

Infection is a clinically relevant adverse event in patients with ventricular assist device (VAD) support. The risk of infection could be linked to a reduced immune response resulting from damage to leukocytes during VAD support. The purpose of this study was to develop an understanding of leukocyte responses during the in vitro testing of VADs by analyzing the changes to their morphology and biochemistry. The VentrAssist implantable rotary blood pump (IRBP) and RotaFlow centrifugal pump (CP) were tested in vitro under constant hemodynamic conditions. Automated hematology analysis of samples collected regularly over 25‐h tests was undertaken. A new flow cytometric assay was employed to measure biochemical alteration, necrosis (7‐AAD) and morphological alteration (CD45 expression) of the circulating leukocytes during the pumping process. The results of hematology analysis show the total leukocyte number and subset counts decreased over the period of in vitro tests dependent on different blood pumps. The percentage of leukocytes damaged during 6‐h tests was 40.8 ± 5.7% for the VentrAssist IRBP, 17.6 ± 5.4% for the RotaFlow CP, and 2.7 ± 1.8% for the static control (all n = 5). Flow cytometric monitoring of CD45 expression and forward/side scatter characteristics revealed leukocytes that were fragmented into smaller pieces (microparticles). Scanning electron microscopy and imaging flow cytometry were used to confirm this. Device developers could use these robust cellular assays to gain a better understanding of leukocyte‐specific VAD performance.     

Sodium pump activity in thymocytes of rats with Goldblatt hypertension

Sodium transport has been studied in thymocytes of one-kidney, one-clip (1K, 1C) and two-kidney, one-clip (2K, 1C) models of hypertension in the rat. No differences of intracellular sodium or sodium transport could be demonstrated in either model when compared with sham-operated controls. The experiments provide no evidence to support the concept that an inhibitor of sodium transport is associated with the development of hypertension in the one-kidney, one-clip rat. A previously unrecognized effect of incubation time and cell density on thymocyte sodium metabolism is reported.     

Effect of the calcium antagonist verapamil on human leucocyte sodium transport in vitro

Sodium efflux rate constants and intracellular sodium were measured in leucocytes from healthy volunteers in the presence and absence of the calcium antagonist verapamil hydrochloride. Verapamil stimulated sodium pump activity and this effect was dependent on the presence of external calcium. Verapamil has been reported to reverse the abnormality of sodium transport seen in leucocytes from patients with essential hypertension and the present study demonstrates that sodium pump activity in leucocytes from control subjects is also stimulated by exposure to verapamil in vitro. This direct cellular effect appears to be due to the calcium antagonist properties of the drug.     

The physiatrist as primary physician for patients on an inpatient rehabilitation unit

Eighty-two patients admitted to a predominantly geriatric inpatient rehabilitation unit were followed throughout their stay in order to document their need for medical management. Their average age was 74.1 years and mean length of stay was 27.9 days. A total of 302 indications for medical intervention (3.7/patient) were found. In addition there were 2.8 medication changes/patient found when comparing admission to discharge medications, and 0.7 medications/patient prescribed for intercurrent illnesses. Actual documented loss of planned therapy time was found 21 times, involving 19 patients but exceeded 1 day in only six patients. Fifty-eight patients were ultimately discharged home, 14 were discharged to nursing homes (7 for social reasons), and 10 were transferred to an acute general hospital. Adverse drug reactions occurred in 27% of the patients and incidence rate paralleled the number of medications prescribed for the patient. This study indicates that the physiatrist on an inpatient rehabilitation unit must function as team manager or program director, and as the patient's primary physician. By managing medical problems effectively, the physician limits the loss of therapy time, thus shortening the length of stay and enabling the patient to continue to participate in his rehabilitation program.