Hearing loss and the high speed dental handpiece.

A pure tone air conduction audiometric evaluation was administered to 137 dentists and 80 physicians. The physicians were found to have better hearing threshold levels, notably in the 4000HZ center frequency range. The left ear of right handed dentists showed a greater loss of hearing ostensibly related to proximity to the noise source. Dental specialists showed a loss pattern similar to those of the general dentists. The findings suggest that there may be a cause and effect relationship between hearing loss and use of the highspeed dental handpiece.     

CRYOGLOBULINEMIA AND CUTANEOUS LEUKOCYTOCLASTIC VASCULITIS WITH HEPATITIS C VIRUS INFECTION

Background. Mixed cryoglobulinemia (MC) is a systemic disorder, characterized by a typical clinical triad: purpura, weakness, and arthralgias, with visceral complications such as liver and renal involvement. The objective was to study the association between hepatitis C virus (HCV) infection and essential mixed cryoglobulinemia (EMC). Patients and Methods. Markers of HCV infection in 11 patients with cryoglobulinemia were examined and hepatitis C virus (HCV) was detected in eight of them. These patients were included in a clinical and histologic study. Anti-HCV antibodies were determined by a second-generation enzyme-linked immunosorbent assay (ELISA-2) in sera and cryoprecipitates. Studies on HCV-RNA were performed by a two-stage polymerase chain reaction (PCR) in the serum. A control group, consisting of 28 patients with other cutaneous disorders, was studied for HCV infection using ELISA-2 and PCR. Results. All patients had liver dysfunction, arthralgias, and purpura. Three patients had involvement of the peripheral nervous system, two had renal involvement, and one patient had Sjögren's syndrome. Cryocrits ranged from 3% to 20%. Six patients had type III cryoglobulinemia and the remaining two had type II. Markers for hepatitis B virus (HBV) were negative in all serum samples. Anti-HCV antibodies and HCV-RNA were positive in the serum of all the cases with MC. Anti-HCV antibodies were positive in all cases except for one of the cryoprecipitates tested. Four patients received recombinant interferon alfa. In two of them, serum aminotransferases became normal and cryoglobulins disappeared. Conclusions. The results strongly suggest that HCV infection is responsible for the cryoglobulinemia and vasculitis in patients with MC and that treatment with interferon alfa is presently the treatment of choice for such patients.     

Selective delivery of chemotherapeutic agents with a new catheter system

A new catheter system was used in ten patients (16 infusions) for infusion of chemotherapeutic agents to the sites of malignant gliomas. Thirteen infusions to the supraophthalmic region were successful, as were three infusions to the posterior cerebral region. There were no complications after the infusions. A neurologic complication occurred in one patient in whom two successful supraophthalmic infusions were previously carried out. In this patient the guide wire separated during catheter placement into the posterior cerebral artery.     

Anterior proliferative vitreoretinopathy. Clinicopathologic, light microscopic, and ultrastructural findings

Proliferative vitreoretinopathy (PVR) involving the posterior and equatorial retina is an established clinicopathologic entity. Clinically, a similar process, anterior PVR (APVR), results in anterior dragging of the peripheral retina by membranes which connect to the ciliary body or iris and cause circumferentially and radially fixed retinal folds. The pathology of APVR, however, has not been reported. The authors describe pathologic findings in 28 cases of APVR and ultrastructural pathologic findings in 6 surgical APVR specimens. Anterior PVR was frequently associated with retinal detachment (RD) repair (96%) and trauma (38%). Residual vitreous at the vitreous base virtually always provided a scaffold for membranes containing proliferating cells and deposited extracellular matrix. Major components of APVR membranes were fibrovascular tissue (71%), pigment epithelial cells (43%), fibrous and corneal stromal ingrowth (32%), and glial proliferation (18%). Because of its anterior location, APVR membranes also incorporated ciliary epithelium and corneal endothelium. Contraction of APVR membranes caused anterior retinal displacement and detachment in anatomic configurations corresponding to narrow and wide peripheral troughs. The authors' findings indicate that APVR is a distinctive clinicopathologic entity which may complicate rhegmatogenous RD and its repair.     

Pathologic processing of vitrectomy specimens. A comparison of pathologic findings with celloidin bag and cytocentrifugation preparation of 102 vitrectomy specimens

Specimens obtained from 102 vitrectomies were processed by cytocentrifugation and celloidin bag techniques. The histopathology obtained with each procedure was compared with respect to cellular and tissue findings. Forty-five percent of cases had identical findings by the two techniques. Quantitative analysis of the discrepancies revealed better cellular recovery and identification by cytocentrifugation, and similar rates for the recovery and identification of tissue elements. Qualitative analysis showed better demonstration of tissue histopathology using celloidin bag thin sections. Thus, pathologic analysis was more complete when the two techniques were used together than when either was used alone.