Evidence for an HIV-related nephropathy: a clinico-pathological study

The existence of an HIV-related nephropathy as a distinct disease entity is controversial. We observed a high incidence of renal disease in our AIDS patients. Of 182 patients, 59 patients (32.4%) were found to have heavy proteinuria (greater than 2 g/24 h). Of these, 24 patients had slow progression of renal insufficiency and 2 patients had rapid deterioration to end stage renal disease. There was a notable absence of hypertension in these cases. The incidence of proteinuria was similar in blacks and hispanics; however 22.8% of blacks had renal insufficiency as compared to 6.9% of hispanics. There was no difference in the incidence of heavy proteinuria between intravenous drug abusers (32.3%) and nonabusers (33.3%). Renal morphology when examined showed characteristic changes, including cytomembranous structures and virus-like particles. These changes were similar in patients with heavy or light proteinuria, though they were less severe in the latter. We conclude that a HIV-related nephropathy exist and the presence of cytomembranous structures and virus-like particles in the renal tissue raises the possibility of a viral etiology for this disorder.

Hyponatremia in patients with the acquired immunodeficiency syndrome

Of 103 patients with the acquired immunodeficiency syndrome (AIDS) admitted for acute opportunistic infections, 36 had serum sodium less than or equal to 130 mEq/l (130 mmol/l). In 12 the hyponatremia was associated with volume depletion and corrected with saline replacement therapy. In 23 it was associated with the syndrome of inappropriate antidiuretic hormones secretion (SIADH). One patient had adrenal insufficiency and the serum sodium corrected after steroid replacement. We conclude that hyponatremia is a common electrolyte abnormality in AIDS patients suffering acutely from opportunistic infections and that SIADH and volume depletion are important contributing factors.

Mutagenesis by transient misalignment

Based upon a consideration of two mutational hot spots produced during DNA synthesis by a eukaryotic DNA repair polymerase, we suggested that certain base substitution errors result not from direct miscoding but from correct coding by a transiently misaligned template-primer (Kunkel, T. A., and Alexander, P. S. (1986) J. Biol. Chem. 261, 160-166). This model, which we called dislocation mutagenesis, has been directly tested. Introducing a single, phenotypically silent G----A base change into the template switches the base substitution specificity at the immediately adjacent hot spot, a T residue, from T----G transversions to T----A transversions. The cumulative change in frequency, represented by the disappearance of the T----G events and the appearance of the T----A events, is greater than 300-fold. These data demonstrate that during DNA synthesis in vitro, a base at one position can code a mutation at another position. This mechanism can operate over greater distances to produce complex mutations as well. We present one example in which a 123-base deletion containing three base changes at one end of the deletion can be precisely explained by transient misalignment. It remains to be established whether mutagenesis by dislocation operates in vivo to produce biologically significant changes in genetic information.

Renal cytomembranous inclusions in idiopathic renal disease as predictive markers for the acquired immunodeficiency syndrome

Tubuloreticular inclusions (TRI) and cylindrical confronting cisternae (CCC) are present in cells of patients with the acquired immunodeficiency syndrome (AIDS) and have also been detected in the kidneys of individuals with AIDS and heavy proteinuria. We examined renal biopsy tissue from 13 patients with proteinuria and/or renal insufficiency. At the time of biopsy, two of the patients had AIDS (group A), four had AIDS-related complex (ARC) (group B), and seven presented without any clinical signs or symptoms characteristic of AIDS or ARC. These seven had risk factors for AIDS, and systemic lupus erythematosus (SLE) was excluded in all. Abundant TRI were present in the renal endothelial and fibroblastic interstitial cells in all patients from group A and B and in four patients who had no evidence for AIDS or ARC at the time of biopsy (group C). These individuals were followed, and all developed AIDS within a period of 3 to 14 months. CCC were detected in two of two patients in group A, one of four in group B, and one of four in group C. TRI and CCC were not present in the renal tissue of the remaining three patients; they did not develop ARC or AIDS over a prolonged observation period. Our findings suggest that TRI and TRF are ultrastructural markers for human immunodeficiency virus (HIV) associated nephropathy and can be seen before AIDS has manifested itself. These structures may be of predictive value for the future development of AIDS in patients presenting with apparent idiopathic renal disease.

Exonucleolytic proofreading enhances the fidelity of DNA synthesis by chick embryo DNA polymerase-gamma

The high fidelity of chick embryo DNA polymerase-gamma (pol-gamma) observed during in vitro DNA synthesis (Kunkel, T. A. (1985) J. Biol. Chem. 260, 12866-12874) has led us to examine this DNA polymerase for the presence of an exonuclease activity capable of proofreading errors. Highly purified chick embryo pol-gamma preparations do contain exonuclease activity capable of digesting radiolabeled DNA in a 3'----5' direction, releasing deoxynucleoside 5'-monophosphates. The polymerase and exonuclease activities cosediment during centrifugation in a glycerol gradient containing 0.5 M KCl. In the absence of dNTP substrates, this exonuclease excises both matched and mismatched primer termini, with a preference for mismatched bases. Excision is inhibited by the addition of nucleoside 5'-monophosphates to the digestion reaction. In the presence of dNTP substrates to permit competition between excision and polymerization from the mismatched primer, the exonuclease excises mismatched bases from preformed terminal mispairs with greater than 98% efficiency. The preference for excision over polymerization can be diminished by addition of either high concentrations of dNTP substrates or nucleoside 5'-monophosphates to the exonuclease/polymerase reaction. To determine if this exonuclease is capable of proofreading misinsertions produced during a normal polymerization reaction, a sensitive base substitution fidelity assay was developed based on reversion of an M13mp2 lacZ alpha nonsense codon. In this assay using reaction conditions that permit highly active exonucleolytic proofreading, pol-gamma exhibits a fidelity of less than one error for every 260,000 bases polymerized. As for terminal mismatch excision, fidelity is reduced by the addition to the synthesis reaction of high concentrations of dNTP substrates or nucleoside 5'-monophosphates, both hallmarks of exonucleolytic proofreading by prokaryotic enzymes. Taken together, these observations suggest that the 3'----5' exonuclease present in highly purified chick embryo pol-gamma preparations proofreads base substitution errors during DNA synthesis. It remains to be determined if the polymerase and exonuclease activities reside in the same or different polypeptides.

Renal ultrastructural markers in AIDS-associated nephropathy

Renal tissues from two groups of patients with acquired immune deficiency syndrome (AIDS) were examined: Group A had severe proteinuria and varying degrees of renal insufficiency, designated AIDS-associated nephropathy (AAN), and Group B had no renal involvement. Control Group C consisted of patients with heroin-associated nephropathy (HAN) with proteinuria comparable to patients in Group A but without AIDS or its related complex (ARC). The most frequent finding, common to both AAN and HAN, was focal glomerular sclerosis. In contrast to HAN, AAN tissue showed mesangial hypocellularity, sparse interstitial infiltrates, severe tubular degenerative changes, tubular microcystic ectasia, Bowman's space dilatation, and presence of multiple complex inclusions both in the nuclei and cytoplasm in a variety of cells. Abundant tubuloreticular inclusions were found in the endothelial and occasionally in the interstitial cell cytoplasm. Nuclear bodies (NBs) were seen in greater frequency, complexity, size, and heterogeneity, and of budding configuration in Group A as compared with Groups B and C; NBs in Group C were mostly of simple types (I and II). In addition, a peculiar granulofibrillary transformation in many tubular and interstitial cell nuclei was observed in Group A. This transformation was rarely present in Group B and was never seen in Group C. Because complex NBs (Types III to V) and various intracytoplasmic and intranuclear inclusions present in Group A are often associated with viral invasion, their presence in kidneys of AIDS patients with proteinuria suggests a viral etiology for AAN.

Pleural cryptococcosis in the acquired immune deficiency syndrome

Pleural cryptococcosis is extremely rare. We report the first case of cryptococcal pleural effusion in association with the acquired immune deficiency syndrome. Pleural effusion without the evidence of pulmonary parenchymal involvement was the initial and only clinical finding leading to the diagnosis of disseminated cryptococcosis. The pleural effusion resolved spontaneously prior to amphotericin B therapy.

Prosopo-affective agnosia and computerized tomography findings in patients with cerebral disorders

Thirty-nine male patients (median age 61, range 19-92) from a neurologic ward were examined by a test for prosopo-affective agnosia (PAA), i.e., impairment in the recognition of facial affect (emotions) with no impairment in the recognition of facial features (PA, prosopo-agnosia). The scores for patients without hemispheric damage were close to those of normal subjects; the scores for patients with right and left hemispheric disease were lower; and the worst performers were patients with diffuse bilateral disease. The relative independence of PAA from PA was re-affirmed. The neurologic findings on 21 patients were confirmed by computerized tomography (CT). On the PAA test, patients with negative CT results had scores close to those of normal subjects; patients with right or left hemispheric disease had lower scores; and the worst performers were patients with diffuse cortical atrophy. All patients who scored 87.5 percent or lower showed positive results with the CT scan, indicating that the PAA test may have some value in predicting positive CT findings. A significant deterioration in the ability to recognize facial affect was evident in the group of 15 patients aged 65 or older.

Stabilized record bases for complete dentures

A step-by-step technique has been described to construct stabilized record bases which allows the dentist to take advantage of undercuts through the use of a resilient denture liner material in the undercut regions. The resilient denture liner material protects the rugae and prevents damage to the casts in the undercut regions during repeated placing and removal from the cast. Shellac denture base material at the posterior limit of the record base permits an easy method of checking the posterior palatal seal. The incorporation of the posterior palatal seal in the record base allows for adequate retention during the recording of the maxillomandibular jaw relation records and try-in procedures. The record bases made by the sprinkle-on technique are preferred to those made using the dough method. The bases are rigid, stable, not easily broken or warped, and fit accurately.