Identification and characterization of an RNA molecule that copurifies with RNase P activity from HeLa cells

An RNA molecule, 340 nucleotides in length and designated H1 RNA, copurifies with RNase P activity from extracts of HeLa cells or isolated HeLa cell nuclei. When the genomic DNA of various organisms is probed with H1 cDNA in Southern hybridization assays, only mammalian DNA gives a positive signal. The gene coding for H1 RNA in human cells is present in one to three copies per cell. The nucleotide sequence of H1 RNA, which shows little homology to the known sequences of its analogs from prokaryotes and yeast, can be drawn as a two-dimensional, hydrogen-bonded structure that resembles similar structures proposed for the RNA subunit of RNase P from these other sources. Part of the hypothetical structure is virtually identical to structures that can be drawn for analogous RNAs from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and S. octosporus.     

Neurogenic bladder due toHerpes zoster infection in an infant

A case is presented ofHerpes zoster (HZ) infection in a 2.5-month-old infant with the added complication of a neurogenic bladder. The patient's mother suffered from varicella during the 18th week of pregnancy. The patient had a typical herpetic rash at the age of 2.5 months, and developed constipation and a neurogenic bladder. While the constipation improved, bladder atonicity led to hydroureters necessitating bilateral ureterostomies. Urinary tract involvement ofHZ is well known in adults and is reversible. To our knowledge this is the first report of such a complication ofHZ infection in infants.Abbreviation HZ Herpes zoster     

Infections caused by Mycobacterium avium complex in immunocompromised patients: diagnosis by blood culture and fecal examination, antimicrobial susceptibility tests, and morphological and seroagglutination characteristics.

The Mycobacterium avium complex, only rarely described as an invasive pathogen in humans, has recently been reported to frequently cause disseminated disease in patients with the acquired immune deficiency syndrome. Between February 1981 and February 1984 at Memorial Sloan-Kettering Cancer Center, 30 patients with acquired immune deficiency syndrome, 3 patients with leukemia, and 2 patients with congenital severe combined immunodeficiency syndrome developed disseminated M. avium complex infection. Mycobacteria were often found in multiple sites both antemortem and postmortem. Blood cultures were a reliable method for detecting disseminated infection, and the new lysis blood culture systems provided an efficient technique for determining the number of organisms per milliliter of blood. Acid-fast stains and cultures of fecal specimens were also helpful in diagnosing infection. Most of the mycobacteria were serovar 4 (77%), and most (86%) produced a deep yellow pigment. All isolates were susceptible to standard concentrations of clofazimine, cycloserine, and ansamycin, but tended to be resistant to isoniazid, streptomycin, ethambutol, ethionamide, and rifampin.     

Analgesic nephropathy

Many questions about analgesic nephropathy (AN) lack clear-cut answers. We present available evidence for and against proposed answers to many of these questions. These include: (1) Is acetaminophen (AC) nephrotoxic when taken as the sole analgesic? (2) Is the combination of acetylsalicylic acid (ASA) and AC more nephrotoxic than AC taken alone, and if so, why? (3) What are the minimum doses and durations of ingestion required to produce analgesic nephrotoxicity? (4) Is the combination of ASA and AC (a major metabolite of phenacetin) less nephrotoxic than that of phenacetin and ASA combined? (5) Does caffeine in combination with analgesics contribute to nephrotoxicity? (6) What is the incidence of end-stage renal disease (ESRD) due to AN? (7) What uniform diagnostic criteria should be established for AN? (8) What are the earliest anatomic and biochemical abnormalities? (9) What are the mechanisms of renal injury? (10) Does AC cause uroepithelial neoplasia? (11) What research might be most beneficial? Based mainly on associations, some strong, we suggest that AN still exists as a cause of ESRD in the United States, where AC/ASA combinations are available over the counter, and in Canada, where they are not. We also suggest that the evidence needed to recommend that the AC/ASA combination be excluded from over-the-counter analgesic preparations still has limitations. A prospective multicenter study comparing incidence related to AC/ASA in the United States and to AC in Canada and the United States may be needed to answer this question. For such a study to be worthwhile, an adequate incidence in both countries is required.     

Microglial involvement in experimental autoimmune inflammation of the central and peripheral nervous system

Microglial cells form a network of potential antigen presenting cells throughout the nervous system. Much progress has recently been made towards a better understanding of their immunological properties. This study examines their activation in 2 models of T cell-mediated autoimmune inflammation of the nervous system, experimental autoimmune encephalomyelitis (EAE) and its peripheral counterpart, experimental autoimmune neuritis (EAN), induced by the transfer of antigen-specific T cell lines. In both models microglial activation occurs at early stages of the disease. Activated microglial cells show an increased expression of MHC class I and II antigens. In EAE ultrastructural analysis revealed that MHC antigen expression is pronounced on perivascular microglial cells, suggesting this cell population may be important for antigen presentation at a site close to the blood-brain barrier. In contrast to EAE, the microglial reaction in EAN occurs at sites remote from the inflammatory response in the peripheral nerve, not only in the spinal cord but also in the terminal projection fields of primary sensory neurons in the lower brainstem. This early microglial activation in EAN suggests that a rapid and remote signaling mechanism can operate following peripheral inflammation. Immuno-electron microscopy revealed that activated microglial cells are also involved in the synaptic deafferentation of spinal cord motoneurons during autoimmune reactions. The rapid involvement of microglial cells in experimental autoimmune inflammation of the nervous system further points to their role as the main intrinsic immuneffector cell population of the central nervous system.     

High frequency breast ultrasound. Hand-held versus automated units; examination for palpable mass versus screening

Four hundred forty-five patients had one or more breast ultrasound examinations with equipment from six manufacturers, operating at 5, 7.5, or 10 MHz. Two hundred seven patients were examined by both automated and hand-held units. In revealing cysts and solid masses, the automated and hand-held units performed nearly identically. Of 198 patients who had screening mammograms, ultrasound evaluation revealed that 85 (43%) had cysts, while 32 (16%) had solid masses. Of the 207 patients who had diagnostic mammograms for a palpable mass, 63 (30.4%) had cysts, while an equal number had solid masses. Of 45 solid masses from both groups that were imaged and biopsied, all 15 that were malignant were palpable. No nonpalpable malignancies were found by ultrasound alone.     

Diet and other risk factors for cancer of the pancreas

The findings of a case - control study of cancer of the pancreas, which was conducted in the Baltimore metropolitan area, are reported. Two hundred one patients with pancreatic cancer were matched on age (+/- 5 years), race, and sex to hospital and non-hospital controls, the latter selected by random-digit-dialing (RDD). All subjects were interviewed regarding diet, beverage consumption, occupational and environmental exposures, and medical and surgical history. Significantly decreased risks were associated with consumption of raw fruits and vegetables and diet soda, and significantly increased risks were associated with consumption of white bread when cases were compared with hospital and RDD controls. A significantly reduced risk was associated with consumption of wine when cases were compared to RDD controls. Risk ratios for consumption of coffee were not significantly different from one, although there appeared to be a dose - response relationship in women. A moderate but statistically nonsignificant increase in relative odds was found for cigarette smoking, and cessation of smoking was associated with a marked reduction in risk. No significant associations were found with particular occupational exposures. Tonsillectomy was associated with a significantly reduced risk, a finding that has been observed for other cancers as well. The current evidence indicates that pancreatic cancer is likely to result from a complex interaction of factors and suggests that the study of its etiology requires a multidisciplinary approach involving both laboratory and epidemiologic components.     

Uric acid metabolism in therapy of glycogen storage disease type I.

Factors which may explain lower serum uric in a new therapy of patients with glycogen storage disease (GSD) type I have been studied. [1-14C]Glycine incorporation into urine uric acid was 0.68% of the injected dose during a 6-day period of frequent high carbohydrate feedings, 0.40% with the same diet and nocturnal nasogastric feeding by Vivonex, and 0.18% in a control patient with GSD type III. Fractional renal uric acid excretion in the patient with GSD type I increased from 11.3% to 26.3% after beginning nocturnal nasogastric feeding of Vivonex. Red cell phosphoribosylpyrophosphate leve,ls were not changed by the therapy. Addition of Vivonex nocturnal feedings to frequent high carbohydrate feedings (1) decreased the accelerated de novo purine synthesis to a level still higher than control and (2) increased fractional renal uric acid excretion.